This is basically the deciding factor for if I'll get the game or not...
Any information is GREATLY appreciated!
yes and yes.
Echelon mode can be played locally or online with anywhere from 1-4 players. If you don't have a full team the uncontrolled characters will be ai controlled and with the leap system you can take control of them at any time.
Infact you can do that plus all the stuff you use in the game will carry over from single player to multiplayer regardless if you play offline or not, the R&C devs always wanted to give players more freedom in gameplay.