Only 2 people have said the M1 Garand?? Come on! this was one of the most used rifles for Americans in WWII!
However, since Myrellian seems to have lots of trench warfare, the M1 Carbine or M14 would be better
Personally, I would prefer the M14 added... by far one of the coolest guns imo... (carbine is kinda weak compared to Garand and M14)
Also, adding a sniper or two could be neat.
I think the M24 would be good, though the Springfield and Dragunov are older, so they might match better. plus,they have cooler names, really. Having a bunch if guns that are all M[number number number] can be a little confusing honestly unless you are really into guns.
What would be cool would be an AMR AW50. Damage would be something like 150+
And maybe add make some way for the ant chick to modify certain guns to fire Incendiary bullets (fire bullets) , like the trench shotgun or the AW50