Nyloc? Noooooo! what a pig, difficult to deal with without ruining anything... we'll manage at the social though.

Those scooter motors look very hefty, personally I'd go for the power, but I can totally see the dilemma you have. Is the space in the bulkhead for weaponry? Will there be any 'dead space' you could sneak some componentry into? Just looking again, is there enough height to place to ESCs over the motors?