As I understand it, there is the Lucas AAA CoD-style title—apparently known as Trigger—and there is this XBLA/PSN downloadable multiple-only type deal.
The hardest part about making a AAA CoD-style game is the multiplayer. Hell do the multiplayer and you have all the systems for the single player. All you need to do is generate the story and content but the mechanics are already completely done.
Just look at the name of the game "First Assault". That means there has to be something coming after it. They are probably doing an XBLA/PWN multiplayer-only version of the game called First Assault so that they can get all the systems down for Battlefront III.
If you already have the infantry combat locked down, then you can focus on all the vehicle-based gameplay that you would need in a full Battlefront III title.
Look at Dice and Battlefield for example. Medal of Honor is just Battlefield without the vehicles.
