Maybe it's just me, but I don't see this "war" ever happening.
I don't know anything about the comic book or wherever this story comes from, just know what I watched.
I dont see how these two groups could go to "war" with the assets (especially the "Soldiers") they have. If they did, it would end up being either a snipefest, too easy to just pick people off or a bunch of close quarters combat leading into hand to hand. This would cause way too many caualties, if the show wishes to keep any realism at all.
Last weeks episode proved obnly one thing: that nobody wants "war" EXCEPT for the Guvnah. Rick doesn't want it, and the rest of the crews don't want it either, including the head "Soldiers", (Daryl and Martinez) they became buddies in the last episode. Sure, there was some posturing and shittalking between them, but they realized they're not so different and developed mutual respect.
Lizard Face has pretty much realized that she makes bad decisions and seems to be leaning back towards the prison gang.
I think before a war can happen, somebody takes the Guvnah out. It will either come from the inside, a defector perhaps from Woodbury or maybe a hit, coming from Rick, Merle, or Michonne.
Another possible route is to set up some type of baited ambush, using Michonne as the bait, of course.
She will not be given up by Rick, no chance..... because
Michonne is a legit bad ass Ninja. She is one of the best tactical thinkers in the group. Her utilizing Zombie "pets" is nothing short of genius. Her skills as far as recon, moving without being noticed are unmatched. She is seriously skilled with that sword and kickboxing. She cannot be given up by Rick's group as I see her as their best weapon, which is Rick will not give her up to avoid war. She could live the longest on her own IMO, or at least would do as well as Daryl and Merle who also have some living off the land training and can take care of themselves.
The only characters I see as expendable right now are:
LizardFace - annoying nag, hasn't served a purpose in a while (aside from a cumdumpster)
Merle - old, broken, can't get along with anyone
Hershel - really old and broken
Carol - Has she ever been anything besides a waste of oxygen?
Of these, I choose Carol and Hershel to be most likely to die.
Also, the Guvnah is absolutely expendable and NEEDS to die soon, he is killing this season.
I don't expect Michonne/Daryl/Carl dying anytime soon, if ever.
I see Carl, Beth, Maggie, Glenn as the future of the group and perhaps civilization. Don't expect any of them to die. They have been putting Glenn into more of a leadership role, which doesn't really suit him, so maybe if any of this group dies it will be him.