Getting in touch with the Garrison... first step.
Being Navy... It will work. However...
Your talking about guys in their 20s... Beer fueled and overworked. I would add in family. This brings the tone down a tad and ensures that your costume participants are able to attend with out fear of being "mauled". Adding in Kids is a blast as well, and the Star Wars costume contest is a great idea. Kids bring in the fun.. adults are great,but kids add the wonder of a child. Also changes timeframe, as family events are afternoon and early evening. Then it can slide into the singles later on in the evening.
I haven't been to Pearl in a long time. Is this on or off base? How about a Parade? have the event set up outside and inside... have a parade "march" up to the USO. Invite the Rebel Legion, advertise in Pearl for a month and have a blast. Its not like you have bad weather.
MWR loves me here. I am slated to have a ton of events to support on base Sasebo. They are still working out a Schedule for me.
Maybe have a screening of the films.. back to back in the background. Tie in the theme of the Jedi helping the galaxy with the Navy's current slogan "global force for good".