All of the following subject to change and correction as needed!
In November 2011, the largest cluster of Endgamers assembles at the Kabetogama camping and fishing resort in rural Minnesota. Jaiden is initially the only person from the Mount Natazhat team to go there, where he is joined by Graeme, Remi, and Ygraine. They bring with them Odin (the Great Dane), a comatose Tamara, and a heavily-injured Doctor Luis.
Over the course of November, Tamara regains consciousness; Devon arrives; a belated Thanksgiving is celebrated; then Tamara departs in time to get caught up in events on the East Coast.
Alia stays in the old Phoenix HQ in New York.
Luther's status is uncertain, but we're hoping to have a scene or two set during Ygraine's visit to New York over the 10th to 12th of November: he could thereafter either stay in the Skinny Brickfront, or Alia and Ygraine could get him out (most likely then or when Alia effects her own escape the following year).
Monica (I believe) remains at Hollis's cabin collects Peyton and heads to Brian's Lighthouse sanctuary in Canada.
Liz is at one with the universe.
Ygraine distributes Liz's parting words, gifts, and requests to each Endgamer as she gets hold of each recipient.
Cardinal crashes a plane into a lake, then goes for a Vegas vacation.
At the start of December, Cardinal gets to Minnesota.
Still in December, a number of still-active Endgamers - Cardinal, Devon, Graeme, Remi, and Ygraine (not Jaiden, both for medical reasons and to leave someone in charge of our base in Minnesota) - go East to asist as best they can around the Siege. Help in evacuating various people is provided. Tentatively, it seems likely that Kaylee winds up with Cardinal, while Ygraine provides Rue with the chance to go somewhere quiet to heal up, recover, and resume martial training.
Cardinal brings Kaylee to Minnesota for at least a few days (to give her a shot at recovery), then goes to pursue his background - and discovers Edward's latest surprise. Presumably it's after he has done so that Doctor Luis gets transferred from Kabetogama to his care, in Edward's bunker/radio station. But Luis might actually wander off on his own before the war gets fully underway, having told Richard to talk to him "after this is all over" (confirmation of date of departure needed from Manhattan).
In January 2012, the civil war starts. The Totally Coincidental Deveaux Society Strike Team (Graeme, Remi, and Ygraine) will pitch in from the start. Jaiden's still recuperating physically (recovery from events in Alaska was initially estimated in months, if I remember right) and is inclined to sit out the most active parts of the war - but does provide training, in both SAS skills and photojournalism (Ygraine, at least, is keen to develop the latter skillset); he's willing to be called on in emergencies, but will prefer roles such as ferrying people across (or under) lakes and rivers into Canada to any 'front line' service. Devon reluctantly accepts that he should wait till he's at least 18 (which comes in May) before fighting in a war, but does undertake serious training.
Rue and any other guests at Kabetogama are presently in an unknown status in this period actively participates in the war, taking further training in assorted combat skills. She also joins Ygraine in studying photojournalism, with Jaiden as a tutor, so that they can document the war and hope to hold people to account afterwards; Ygraine and Jaiden can tutor her in how to gather evidence and present a case to withstand academic and journalistic scrutiny.
Monica and her family (Nana and Damon, who don't survive) volunteer early in the war to provide medical support behind the front lines.
February/March(?): Alia realises that things are only getting worse, and that she'll run out of supplies before New York calms down again. She uses her power to hitch a ride on a military train out of the city; upon reaching Minneapolis, she calls Ygraine for pick-up. Thereafter, she is based in Kabetogama, but will join up with the field team when access is required to a particularly secure or wholly-offline system.
If he's not already got out of NYC (and wants to), this might be the best opportunity for Luther to escape the misery of Manhattan.
Spring: Sable hooks up with the Endgamers, and starts an active field role. Given her ability, she'll pick up relevant skills extremely quickly. She wants to check up on Delilah throughout the war, but that should be easy enough to arrange.
Summer: With the civil war now at a 'frenzy', Devon starts actively participating. Rue heads off to Chicago to check on her parents.
August(ish): Devon makes contact with Hana and proto-Wolfhound. At some point - then or later - Rue does so as well. It might make sense for us to run a mission out towards Chicago, to put Rue close to her parents, and give the departing duo protection and company as they shift to Hana's team.
September: A failed assassination attempt on President Mitchell probably doesn't involve any of us…
February/March 2013: Remi realises she's pregnant, and withdraws from active service in the field - but remains at Kabetogama as a lynchpin of its defence.
24th of November: General Moritz nukes Portland and EMPs Seattle.
18th of January 2014: Raven Rock is stormed; Moritz commits suicide; Mitchell is captured. This could involve some of us: certainly, it's the sort of thing Ygraine would be up for. Ygraine and Jaiden both participate: any sealed facility has to have water pipes, while Ygraine can take a team into any opening (pre-existing, or blown wide) large enough to fit through.
18 hours later, loyalist forces are ordered to surrender. Officially, at least, the war ends…
Monica disappears after the war, though Peyton's child periodically receives gifts.
Assorted Dates Throughout the War: Raytech super-science kit happens to fall of the back of a truck in close proximity to those working as part of / with the Endgame team. What a coincidence! And what fun toys! (I have been promised that randomly-appearing death spiders will be kept to a minimum)
Post-War: Officially, Endgame's job is over - the game for which it was designed has concluded. In practice, even those of us without a posthumous commission (of one sort or another) from Liz are likely to retain varying degrees of ties.
In 2015 Jaiden and Remi marry, as one particularly noteworthy excuse for gathering an array of us in the same place.
2015-16: the war crime trials take place in Albany, New York. Ygraine will be heavily involved throughout, feeding information and analysis from the Liberty databases into evidence. She, Rue, and Jaiden each have their own photographic documentation of events witnessed and scenes discovered. Devon additionally has the pre-war data-store of Endgame's intelligence. At the very least, testifying might put a number of us in touch with each other - checking dates, seeing if any photographs or refugee witness testimonies are available to corrorborate recollections, etc - even if we don't physically meet up during it all.
Edit: 7th February: a few updates.
Edit: 8th February: Raven Rock participation update.