But is the threat of imminent death the only kind of dramatic tension, the only way to have an emotional stake in what happens to these characters?
I was on the seat of my pants throughout Tower of Babel -- not because I was worried that, say, T'Pol or Ensign Kirk were going to die, but because I honestly wasn't sure if the Rigel worlds were going to enter the Federation and the First Families be overthrown by book's end. I may have known that Sam Kirk would survive his hostage ordeal, but I was just as invested in Grev. I may know that Archer will become president in two decades, but I didn't know if he'd be thrown in jail in the meantime. I may know that Trip will survive to at least 2238, but I'm really intrigued by what being in Section 31 does to him -- and through him, in the history of Section 31; how does the organization degenerate into the morally corrupt organization of pseudo-fascists we're familiar with by the 24th Century? How will Trip get out, and what will it cost him?
For the record, these are the fates of the ENT characters we know so far:
Archer - Established in To Brave the Storm to survive until at least 2186, when he is serving as Federation President during the 25th anniversary of the founding of the Federation; the biographical screen aboard the USS Defiant in "In A Mirror, Darkly, Part II," establishes that Archer served as Ambassador to Andoria from 2169-2175 (it doesn't say whose, or why the Federation or its members would need ambassadors to another Federation member state when they're all part of the union), Federation Councillor for United Earth from 2175-2184, and Federation President from 2184-2192. It is unclear if a barely-legible computer screen is considered binding canon. An unused second page of that computer file established that Archer survived until 2245 and died in upstate New York the day after attending the christening of the first USS Enterprise, but this is not canonical since it was never onscreen. In the alternate reality created by Nero's downtime temporal incursion into 2233, it is possible that Archer may still have survived, possibly serving as a Starfleet Admiral again, with his beloved beagle used as a transporter test subject by Montgomery Scott (Star Trek [2009])
T'Pol - Survives at least until 2186, where she is serving as an ambassador and living in outer ShiKahr on Vulcan with Trip, who is using the false identity of a Human gardener for T'Pol's clan named "Michael Kenmore" (and not hiding his secret very well, apparently); they have two teenaged children, a girl named T'Mir (aged no more than 20), and a younger boy named Lorian (To Brave the Storm)
Trip - Beyond the above, he survives under a false identity at least until 2238, when he encounters the young James T. Kirk at a Federation Day celebration in San Francisco (Last Full Measure)
Hoshi Sato - Survives until at least 2186, when she holds a doctorate and lives on Tarsus IV (To Brave the Storm); her biographical file aboard the Defiant says that she retired from the Federation Starfleet with the rank of lieutenant commander, presumably some time in the 2160s, and that she was responsible for the development of the linguacode translation matrix, but it is unclear if this is binding canon ("In A Mirror, Darkly, Part II"); an unused portion of that same bioscreen established that she eventually married Takashi Kimura and retired to Tarsus IV, where she and her husband died in 2246, two of the victims of Governor Kodos from TOS's "The Conscience of the King;" Christopher's use of Taskashi in Rise of the Federation is a reference to this unused portion of her biography, and he may use this fate, but the information from that second part of the screen is non-canonical since it never appeared onscreen
Malcolm Reed - COULD DIE AT ANY MOMENT!
Travis Mayweather - COULD DIE AT ANY MOMENT!
Tobin Dax - Has to survive long enough to transfer the Dax symbiont to Emony, who was apparently young enough to compete in the 2224 Olympics on Aldebarron (Lives of Dax short story "Old Souls"), implying he needs to survive until at least circa 2215.
Phlox - COULD DIE AT ANY MOMENT!
Soval - COULD DIE AT ANY MOMENT! Also he'll have the USS Soval named after him in the 2360s
Thy'lek Shran - Although Federation: The First 150 Years establishes that he will eventually serve on the Federation Council, this book is not in continuity with Rise of the Federation, so it could be honored or contradicted at will. So he indeed COULD DIE AT ANY MOMENT!
Samuel Kirk - Will need to survive long enough to father Tiberius, but, once that's done, COULD DIE AT ANY MOMENT! (Or, he could turn out to be a great-uncle of Jim Kirk, in which case he COULD DIE AT ANY MOMENT!)
Takashi Kimura - Again, established in non-canonical bioscreen to survive until 2246, when he dies with his wife, Dr. Hosh Sato, on Tarsus IV at Kodos's order, but this is non-canonical, so he could still DIE AT ANY MOMENT!
Thanien - COULD DIE AT ANY MOMENT!
Bodor chim Grev - Could DIE AT ANY MOMENT!
Valeria Williams - Needs to survive long enough to give birth to Tiberius Kirk, if she is supposed to be James T. Kirk's great-grandmother. Once Tiberius is born, or if Christopher later decides she won't be Jim's ancestor, she COULD DIE AT ANY MOMENT!
Reynaldo Sangupta - COULD DIE AT ANY MOMENT!
Therese Liao - COULD DIE AT ANY MOMENT!
Regina Tallarico - COULD DIE AT ANY MOMENT!
Michel Romaine - COULD DIE AT ANY MOMENT!
Elizabeth Culter - COULD DIE AT ANY MOMENT!
Pedro Ortega - COULD DIE AT ANY MOMENT!
Bryce Shumar - Fated to die along with the crew of the USS Essex in orbit over Mab-Bu VI in 2167 (TNG: "Power Play")
Caroline Paris - May be one of Thomas Paris's ancestors, or may just be a distant aunt. Unestablished. If she's to be his ancestor, she'll need to survive long enough to have a child. Once that's done, or if she's an aunt rather than a direct ancestor, then she COULD DIE AT ANY MOMENT!
Steven Mullen - Fated to be promoted to second in command aboard the USS Essex and die in 2167 (TNG: "Power Play")
Miguel Avila - COULD DIE AT ANY MOMENT!
Thoris - COULD DIE AT ANY MOMENT!
Haroun al-Rashid - Fated to serve at least one full term as Federation President; the Palais de la Concorde will be completed during his term and some historic debates will occur there between him and Councillor sh'Rothress over the qualifications for Federation membership (Articles of the Federation)
T'Maran - Fated to serve at least one full term as Federation President (Articles of the Federation)
Avaranthi sh'Rothress - Fated to serve at least one full term as Federation President (Articles of the Federation)
Thomas Vanderbilt - Has completed his term as Federation Council President, so he COULD DIE AT ANY MOMENT!
T'Pau - Must survive until at least 2267, to preside over Spock's cancelled weddeing (TOS: "Amok Time"); though, really, enough 24th century novels have used her that she's apparently damn near immortal
Gora bim Gral - COULD DIE AT ANY MOMENT!
Danica Erickson - COULD DIE AT ANY MOMENT!
Marcus Williams - COULD DIE AT ANY MOMENT!
T'Rama - Has to survive long enough to give birth to Sarek, but, after that, COULD DIE AT ANY MOMENT!
Skon - Has already sired Sarek, so he COULD DIE AT ANY MOMENT!
Sobon - Fated to help cure T'Prynn on Vulcan in 2267 (Vanguard: Open Secrets)
Garos - COULD DIE AT ANY MOMENT!
The Three Sisters - COULD DIE AT ANY MOMENT!
Harad-Sar - COULD DIE AT ANY MOMENT!
Devna - Must survive long enough to become trapped in Elysia (TAS: "The Time Trap"); she will continue to serve on the Elysian Council when the USS da Vinci visits Elysia in 2376 (SCE: Where Time Stands Still)
Maltuvis - Must survive long enough to become as legendarily evil a tyrant as Hitler (TOS: "What Are Little Girls Made Of?"), but once that's done, COULD DIE AT ANY MOMENT!
Agent Harris - COULD DIE AT ANY MOMENT!