Online copyright infringement is easy to prove/disprove by analyzing html code. Simple question-if you copied the code any competent lawyer can bust you. If you didn't they don't stand a chance, but you gotta deal with the legal fees and/or headache anyway. Good luck.
Yep-ITU app. Www.uspto.gov.
Look up 'trade dress'
Probably yes. The issue is 'likelihood of confusion' - in other words would the public be confused into thinking the stuff you're selling was affiliated with the dudes with guns. If so, ur busted. If your making fun of them, which is not a bad idea these days, consumers won't believe you're the navy so you're cool. Good luck.
Yep-but it's a lame name anyway. Get creative dude....