yeah max right now is 10v10, i doubt they'll even show the 32v32 warzone stuff this weekend
the lobbys do show two things, the type of input the player (controller for everyone i've seen so far) and platform (PS4 only this weekend). they will allow cross play this release, but not sure exactly what the rules are on inputs, console vs pc, etc
lot of weapons, 8 ARs 6 SMGs then more shotguns, LMGs, DMRs, and snipers. Usual tweaking of weapons, its not like WW2/BO4 where you have a pick-10 system, instead it just seems you can have up to 5 diff attachments on a gun, 3 perks, and 2 lethal/tactical. Classes have some minor abilities but no "superpowers" like BO4.