I would personally recommend just forcing both teams to use the host's console to make their own "Default Classes." This only allows 5 custom classes per team and it'd take a little while to set in between matches since everyone has to put all their classes on ONE 360, but I honestly don't see you guys unlocking every gun/perk in split screen within a few hours. Even if you do, many consoles will have discrepancies with pro perks. Not saying my solution doesn't have that issue either, but at least everything is unlocked right off the bat and pro perks are only available to those who grind them out.
EDIT: Saif- if you could bring some HDMI cables Saturday, that'd be great. I told people to bring consoles and I'll be bringing some monitors. They're more or less new though so I don't have HDMI cables with them.