Sounds like you got a good pre-trip plan goin on. I always like to keep about a 10ton bottle jack for the trailer, in case of a flat tire. I would place it right under the axle and it lifted it up with no probs.
a good set of wrenches, ratchets, sockets, screwdrivers, etc would also be a good thing to keep on board.
zip ties (a man's best friend), wire strippers (for all those lights) black electricians tape, electrical connectors.