This could be sand of a savanna, a desert, or the rocky part of a beach, or even an edge of a canyon where Flik's purplish ant colony lives. If not Grasshoppers again, you could let the bug villain be some big bug like the Mosquito swarms. deciding what sort of land you want these ants of Flik's colony on would be one of the first questions to form the new characters.
Friendly Bat colony
Tree Swallow Flock / Cliff Swallows, equally good choices on such grounds
If we wished to do some funny war scene that could be like Toucans being led towards the lizards because the lizards were on the villain side. Elf Owl scaring the new villains in this sequel. Cactus Wrens keeping the big garden Flik's colony grows safe. Friendly Bats chasing the villains Hummingbirds feeling glad to chase the villains to thorny flowers before they meal time of sucking on the flowers. Quails letting Flik's colony take things like poppies and grass or similar small things.
These ants in Flik's colony could use something like the sharp points of thorns on roses as their puny swords to fight their enemies.
You can look a bit on Dreamworks Wiki and check Praying Mantis in Kung Fu Panda to help you figure out the war scenes too. It's also the wiki that mentions Pixar in Antz movie information.