I have a thought but not for-sure how much help I could be.
Have the groom and groomens in their "marine uniforms"
Im guessing the batman is his idea?! Have a Batman grooms cakes
The over all colors and theme Tifffany's colors. I feel will be very whimsy and elegant.
"But most of all make it fun and your own... its whatever the two of you want and feel that you cant go without."
I think the best way to do it elegantly is to do incorporate these themes in the details. Otherwise it can be too overwhelming or gimmicky. For example, you could give out party favors in Tiffany bags. Or do try what this couple did: http://wedinator.files.wordpress.com/2010/10/superhero-wedding.jpg and hide batman shirts under the men's suits.