Janeway presents Starfleet Command with a very Kirk-like situation: they either have to promote her or send her to prison. Politically, sending the hero of Voyager to prison for her actions is disastrous, not to mention the PR blow that comes from revealing that a Starfleet crew trapped all alone did not live up to Starfleet's ideals, and in fact committed crimes. That all needs to be handled quietly.
Making Janeway an Admiral is the easiest way to put her where she cannot command a ship when the public believes she is a hero.
Chakotay may well leave Starfleet. Someone will make it clear to him that he's probably never going to have a ship of his own, and it will take a long period of good behavior before they'll even let him be someone's XO. He might get offered something like Sisko's old job (I mean the one at Utopia Planitia, not DS9). I actually see Chakotay being quite happy to resign from Starfleet again, and become a political leader on his home world.
Tuvok, ... Well, the Titan novels make him Riker's Tactical Officer, and that works well enough for me. Of course, that does make him seem kinda cursed, as the poor guy keeps getting assigned to ships that accidentally wind up decades from home.
Tom Paris was actually a bad fit for Starfleet to begin with, but I see him being a very happy (and good) stay-at-home dad. Maybe a successful writer, maybe nobody likes his holonovels but Harry. That doesn't matter, as the job where he finds his fulfillment is being a dad.
Torres is either working somewhere like the Advanced Starship Design Bureau, or is the Chief Engineer aboard a ship, doing the Scotty thing for some lucky Captain.
Harry Kim gets bumped to Full Lieutenant immediately, and is definitely on the "fast track": they expect great things of him, and put him where he has the chance to excel. A year aboard one ship and his heroic actions leading an away team get him made a LtCmdr and made somebody's XO. Within the year he's done something else amazingly heroic, and becomes a Commander and XO of a bigger ship. A couple of years there before they are offering him his own command.
Seven is going to be having a number of LONG conversations with Starfleet Security, and probably the Corps of Engineers and such. Eventually she finds some kind of work she find fulfilling, although it is something that surprises her as well as us. Perhaps she takes Boothby's job.
The Doctor becomes a General Practitioner on a fairly developed colony world. He spends his spare time exploring his still growing sentience, and his days helping people stay healthy and helping their children grow up healthy and sane: in effect, the entire community is his family.
Icheb joins Starfleet Academy for real, and Captain Kim requests him for his crew when he graduates.
Neelix continues to work with Project Pathfinder, with the eventual goal of allowing worlds first contacted by Voyager to join the Federation if they so desire, and making travel between the Delta and Alpha Quadrants regular. They all know it might take more than their lifetimes, and they all think it is worth it.
Voyager itself goes in the Fleet Museum. Temporal Investigations removes all the high-tech doodads (and debates at length sending agents back in time to prevent the ship having used them in the first place, but eventually agrees that is too risky, and the contamination can be contained). It gets a birth of honor among the other vessels of great historical significance, like the Constitution Class USS Excalibur (last surviving pre-refit Connie), the Enterprise-A (last surviving post-refit Connie), and so on.
Soon, Starfleet gives the name Voyager to a new class of long-range explorers, and invites everyone who served aboard the Intrepid Class ship to the christening of her Class Vessel.
But it's not just Icheb's story, it's going to show what VOY left behind in the DQ.
