I think the rts behavior can do all this, but it would take a lot of wrangling on the events.
Probably more than you should mess with pre beta imho.
If you want to play with stuff to see how it would work out, I would suggest for your melee characters you set the range to 1, then on the on shoot event you could have it change animation. Then for the hit you could work out some probability of a hit. To prevent the melee's from attacking over one another, use the rts condition object to avoid.
Your ranged should be pretty straight forward, but you might want to add some event that makes them move away from targets then fire.
Same goes for support, and commanders.
One thing to consider is the type of view your dealing with, if this is top down, then no problem.
If you want something like side view or isometric, things will get a little tricky with z order.