Hi, As fleet play should be a large part of this experience could you create some group/ fleet missions?
I'm thinking a set objective mission for different numbers of players. Perhaps a set battle against a cpu fleet or strategy game i.e stop enemy fleet breaking out of an area. ( sort of like the uk grand fleet bottling up the KM fleet in to the north sea in ww1)
I would suggest either fleets as in organised fleets or perhaps and open mission much like raiding in other games a group can drop into a room do a group mission.
Make them tough, make the team work essential and in return put out very good xp and or credits for success.