Recent previews (sorry I can't recall which one, they all start to jumble in my head, either IGN or gamespot IIRC) indicate that there will be NO coop mode, likewise the "other creatures" are Trandoshans.
Does this mean you cannot be battle droids? No word on that yet, but Clonetroopers vs. Trandoshans are confirmed.
I would love to see an Assault/Siege type gamemode with vehicle support, classes and objectives, but I have yet to read about it being confirmed...
Limiting games like JA to 16 recommended players makes sense with all the extra saber combat code that is used to send to clients and the animations, etc. but I don't know about these other games. There's no melee combat that we know of (although RC seems to have "punching" and Vibroblades or possibly both of those combined). Though I'm betting that RC's melee combat will be more the vanilla FPS style "zero range gun" gauntlet/fist/axe/chainsaw variety rather than the versatile Lightsaber we're used to in the JK series.
Did I hear that Battlefront would have "special characters" like Jedi? If these were controllable one might expect melee combat. But on the other hand it may be incredibly simplistically done, since what would be the justification for doing an elaborate melee system when it's only going to be applied to the rare special character?
So theoretically, less detailed graphics, and less detailed data to send to clients = possible to have more players at once.