[Sombre]

Yes the AI is smart enough to have flying units walk/hop/slither along until they are in range to fire their weapons. It can be observed with Caelian shortbows in the CB mod quite regularly. So javs would work fine.

I like the idea of Caelum adopting ermorian style tactics. Roman troops were copied by several nations in the time of the empire, right?

It's slightly harder to manipulate the vanilla graphics than you might think though, due to a lack of 'perfect' vanilla sprites - there are methods but I'm not a fan of them and they are quite time consuming. Something like sticking an ermorian style tower shield on a spire horn troop should be easy, but it really isn't.