^^you can trade away the technologies you have researched. You can't broker the technologies you got via trades.
simultaneous: all teams play during the timer period, with no particular order. Turn ends when the timer is over OR all teams ended their turn.
sequential: there is a team order and a timer for each. team 1 has to end its turn or go over its timer before team 2 can do anything. So typically a sequential game can be very long.
I wonder how you voted previously if you are still confused with this