Virgin Atlantic will probably move to the TBIT.
Volaris, Sun Country, TACA, and Avianca don’t require a whole gate to themselves, while Virgin America and Spirit require several gates. Hawaiian requires several A330 capable gates at particular times of the day but doesn’t need a gate all day long.
Would not be surprised if Air Canada goes to Terminal 6 - this would make it a lot easier for them to connect to United. I believe that under this agreement Delta and American would no longer require gates in T6, so that would open up a lot of space there. TACA and Avianca could also go to T6, both being Star Alliance carriers.
Aeromexico may stay in T2 to facilitate better connections with Delta.