Momiji has zero of those "survival skills" that might be helpful in these kinds of situations, so he'll be huddling hungry away from the rain and then fleeing robots and plant-monsters. More capable folks he can hide with/get rescued by would be handy.
And then he'll promptly get hit with a love dart, which will be a whole 'nother mess. (...ngl, I kind of want someone whose reaction is "absolutely not" to have to drag him past killer-robots or whatever to safety.)
Potentially deciding that the tentacle-plants seem friendly and then being surprised by how correct he is.
General post-apocalyptic survival huddling would also be nice. Momiji'll probably learn to get somewhere safe and stay put after his first couple adventures, so he's available to handle fumbling first-aid and similar minor assistance for those getting more into the action-adventure side of things.
Momiji Sohma | Fruits Basket
Canon: Fruits Basket
A5: Here!
Permissions: Here!
Plans: