I'm re-reading the post series DS9 novels, so it's hard not to let them color my perceptions, since I liked a lot of what they did, but I'll try anyway:
Kira, struggled for a bit taking over for her friend and Emissary, but oversaw the station through the post-war years. She surprised herself by becoming an advocate for Bajorans to aid the Cardassians in their struggle to recover from the Dominion's retribution. In 2399, she finds herself as the Bajoran ambassador to Cardassia. She has several enemies in the Vedek Assembly and the Bajoran Government who disagree with her stance on Cardassia, all of which convinces her she's doing the right thing.
Ezri Dax struggles to find her place on the station. While she finds herself enamored with Julian, she constantly wonders if it's her or Dax that has the strongest feelings for him. The stresses of the war meant Dax was kept quite busy as many on the station found themselves struggling with PTSD. It seems many chose to ignore or suppress those feelings during the war, but afterwards, many found they could not relax as easily and without the constant fear of death, many finally had no choice but to confront what was going on with them. Dax worked with Dr. Bashir to create new therapies to treat these cases. This caught the attention of Starfleet HQ, who recalled Dax to Earth to oversee counseling for all of Starfleet, creating a new office, as head of Counseling at Starfleet Medical. At this time, she and Julian realized both of them were looking for something else. Julian, while he loved Ezri, still pined for Jadzia. Ezri, on the other hand, was looking for someone to be her stability. Realizing she needed to find that for herself, she left for Earth. In 2399 she's still the head of Counseling at Starfleet Medical and is overseeing research into the long-term effects of the Borg Invasions and Dominion War on the current leadership in Starfleet.
Julian Bashir kept resisting calls from both Starfleet and Section 31 to work for them, directly, preferring to remain on DS9. During an especially heated political debate over Bajor helping Cardassia, Kira tasked Julian with looking into Dr. Galen's research and the discoveries by several races on Stardate 46731.5, specifically showing that Bajorans and Cardassians shared common ancestry. His work saw him pursue leads to the Preservers and a possible connection to the Founders, after noting a similarity between the ancient humanoid and the Female Shapeshifter. Realizing he could not longer operate from a static position, he requisitioned a ship and crew and headed off. In 2399, it's been a few years since anyone has heard from Bashir or his crew. Stories pop up here and there, most indicating he did pursue the connection to the Founders and is somewhere in the Gamma Quadrant.
Odo preferred focusing on his people, content that his friends, colleagues, co-workers, and Quark would all get along without him, as his people needed him more. However, at one point or another, most, if not all of them found their way into the Gamma Quadrant and to Odo, even Quark, who wanted to discuss a franchise opportunity for the Dominion to open their own Quarks Bar and Casino. Odo found himself begrudgingly welcoming them and giving them all advice, before letting them go on their way. He did, however, find Bashir's findings to be of great interest, serving as a liaison between the doctor and the Female Changeling. This opened up a new avenue in Bashir's research and he set off on a new direction, though, again, as of 2399 no one has heard or seen of him or his crew in years. Odo notes, with some sadness, that as of 2399, Kira is the only one who has not visited him. He understands, but still hopes that one day, she will come to him.
Nog quickly assumed the role of Chief Engineer of DS9 and the Defiant. He oversaw the first upgrade of the station since the weapons array was added. This upgrade includes bringing the Cardassian systems more inline with the LCARS system, shielding the station from plasma disruptions, such as the one that necessitated an almost complete evacuation in 47182.1, as well as general defensive and offensive upgrades. He found himself wondering how much of the original station was left by the time he was done. By then, even his uncle found himself impressed, as his holosuites benefited greatly from the upgrade. This garnered him much attention and he soon found himself promoted to Captain and put in charge of a crew made up of Starfleet Core of Engineers members, consulting on upgrading and integrating technology as a means of brokering peace between species. Sadly, in 2398 he was killed in action. O'Brien found Nog's notes on Vic, who he had taken extra care to protect during the station upgrade. Working with Dr. Zimmerman, the two created Emergency Engineering Holograms in Nog's image, capable of lasting years if need be on ships designed to go further and further into deep space. Much to their surprise, each Nog hologram had an unusual tic where it kept advertising for the various Quark Bar and Casino franchises throughout the Alpha and Beta Quadrants ("And, coming soon, the Gamma Quadrant as well!")
Quark was contacted by Rom, now the Grand Nagus with a lucrative offer. Rom, concerned with public opinion regarding the Ferengi, sought to work with his brother to expand the bar into a franchise. The hope would be that as the bar opened up throughout the quadrants, people would learn that there was more to the Ferengi than their reputation would have many to believe. By 2399 Quarks could be found in almost every non-Federation outpost, with some starbases actually including them, as well. While Quark is happy with this, he is unhappy when he notices that Rom has been talking with the Federation. It turns out that Rom's plan was, ultimately, to convince the Federation that Ferenginar was a suitable candidate for entry into the Federation. This drives Quark to head into the Gamma Quadrant, hoping to open some bars far away from Federation territory, much to Odo's discontent.
Garak struggled to remain plain and simple, but found himself thrust into the spotlight as a hero on Cardassia. It did not escape him that many different parties benefited from this. The side that wanted Cardassia to evolve and move past the tendencies that drove them to aligning with the Dominion saw Garak as an example of someone who risked everything to save Cardassia. The traditionalists, who wanted Cardassia to return to a strong military, one that would not have needed to join the Dominion to crush its enemies, saw Garak as a symbol of everything wrong with Cardassia and a fine scapegoat for its current problems. Despite calls for him to take a leadership position, Garak found a way to work behind the scenes and survive. By 2399 he finds himself as Kira's counterpart, the Cardassian ambassador to Bajor. Sometimes, wistfully, he realizes that he has more allies among the Bajorans than he does among his fellow Cardassians. Therefore, he relishes the adversarial and uncertain relationship he has with Kira, who, though she respects him, still finds him repulsive, despite the fact that they both truly want to see a lasting friendship between their species.
The Siskos have settled on Bajor and Kassidy gives birth to Jadzia Jennifer Sisko (affectionately called J.J.) in honor of two women Ben had admired, respected, and mourned. Kassidy admitted to Jake that he hoped the name would draw Ben's attention and prompt his return. While Kassidy found the people of Bajor to be most welcoming, she did miss her job, as well as the people on DS9, though with each year, she recognized fewer and fewer of them on her trips to the station. When J.J. was old enough, Kassidy began going on runs as a freighter captain again, sometimes leaving J.J. with Jake and sometimes taking her along. By 2399, Kasidy Yates Interstellar Freights became the largest non-Federation freight company in known space, helped partly by its status as the sole freighter of Quark's Bar and Casino. Despite only handling Quark's legitimate business, it's still enough to keep it going.
J.J., much to Kassidy's dismay, followed in her father's footsteps at by 2393 had enrolled at Starfleet Academy, eager to beat the longstanding record, set by Sylvia Tilly, of being the youngest candidate accepted to the Starfleet Command Trianing Program.
Jake, meanwhile, stayed on Bajor to help Kassidy, but was soon persuaded by her to pursue the fellowship at Pennington School. He arranged with her to come and visit as much as possible, watching J.J. during some of those visits, so Kassidy could get back to captaining her freighter. As she grew into a teenager, Jake found himself drifting away from J.J., realizing, with Ezri's help, that he did so because J.J. was becoming more and more like his father. He finally published Anslem, based largely on his own experiences. In 2399, Jake is a father to his own son, Benjamin Nog Sisko in honor of his father and best friend.
Ben Sisko has been there for all of this, in one form or another. Being non-linear, he has been able to drop in on his friends and family often. Each time he seeks to explain to the Prophets how their existence inspires, affects, and is affected by each and everyone of them. He knows, because he has seen it/done it/is doing it, that he will return early in the 2400's to oversee a period of great upheaval. Though he knows the people he cares about will be overjoyed to see him, he knows it will be bittersweet as it will be a portent of what is to come.
NOTE: I forgot about Worf! Worf initially enjoys his new position, but struggles with missing Starfleet. Martok even notes that Worf never fully resigned his position, opting instead for a leave of absence. This is made worse, when, after rejoining the crew of the Enterprise briefly for the wedding of Will Riker and Deanna Troi, he found himself drawn into the whole mess with Shinzon.
Returning to Qo'noS, Martok confronts Worf about this. Worf, as usual, denies it and states his allegiance is with Martok. Martok, realizing he must make the decision for him, fires Worf and instead hires Alexander. Worf returns to Starfleet and is promoted to Commander and then Captain. Struggling with being assigned to aid the Romulans affected by the Hobus Star, Worf sees Picard's resignation as a sign and chooses to resign his commission in solidarity with his former commanding officer. He finds himself at the Picard vineyard shortly thereafter.
Knowing his former Captain, Worf provokes Jean-Luc, hoping that by doing so he can help him reach a catharsis, similar to what happened on the Enterprise during their trip to the 21st Century to prevent the Borg from stopping First Contact. He does succeed in provoking Picard, but Picard is unable to reach a catharsis, leaving Worf realizing he has no idea what to do next.
After consulting with Ezri at Starfleet Medical, Worf decides he will use his influence with the Klingon government to help as many Romulans as possible. With Alexander and Martok's help, he establishes a home for Romulan children who lost their parents. By doing so, he hopes he can finally put aside his anger towards them for the death of his parents at Khitomer. Much to his surprise, he finds himself attracted to one of the Romulans overseeing the children, who he begins a relationship with, eventually marrying her.
In 2392, Martok dies and Alexander is named the Arbiter of Succession, choosing his father for the role of Chancellor. He is challenged by Toral, but wins. His years as Chancellor are difficult, as many Klingons resent his Romulan wife, viewing her as a spy. However, Worf pushes for a union of the Klingons and Romulans, arguing that the Klingon Empire is strongest when allied with the Romulans and weakest when it is at war with them.
The Klingon/Romulan alliance is seen as a threat to the Federation, which Worf notes, sadly, seems to be suffering due to the corruption at the heart of Starfleet. When in 2399 it is revealed that the Romulans were behind the attack of Mars and a fleet of Romulan ships almost got into a battle with a fleet of Starfleet vessels, things are as strained almost to the point of breaking.
Worf must now navigate this and determine how to unite the three biggest powers in the Alpha/Beta Quadrants, or see a war that could devastate everything.
