As far as the legalities, you can do what my husband and I did--go to the courthouse to get the marriage license and return a few hours later (because the judges took a long lunch) and have a judge take care of legally wedding you, and then have a family friend play wedding supervisor (AKA officiant).
As far as hair, this is what I did: old wedding photos! Warning: lots of photos!
Up towards the top I have my veil, and then towards the bottom we took the veil off so you can see the actual hair. It's just an idea of something to do. The blog is the photographers' blog, so they have lots of weddings and engagement sessions for you to look through as well to get ideas.
As far as tummy things, get something that you're comfortable in. After all, you're going to have to wear it, and if it's a good piece, you can wear it for other occasions. I like the idea of being able to go to the bathroom if you need to and not having to undress in case of a pee emergency.
I can identify. I like the fact that I'm me whether I'm in my pj's or in plain jeans and a top or decked out strutting my stuff. I think part of my love-hate relationship with V-Day is that I do like the reminders that I'm appreciated and loved, but that the whole idea of making a one day super stress test is sickening. One day isn't going to determine whether or not I'm loved or if I love, and I have to remind myself of that this time of year. I love and I'm loved whether I'm all fancy with my hair perfect out at a restaurant or if I look like I just woke up and I'm playing xbox, or anywhere in between. Sure, sometimes we both need a kick in the butt to do the cuddly mushy gushy lovey stuff, like go out to dinner and a movie, but that's us. I'd much rather spend the night in with my best friend, who so happens to be my SO, and have super awesome cuddle-tickle-giggle-shoot zombie time than have us both be out of our element, awkward and uncomfortable and not enjoying ourselves.
tl;dr: fuck the rest of the world. have a tickle-cuddle match instead or make cookies or whatever you want to do. enjoy being together, and fuck everyone else.
"YES. DO IT WITH CONFIDENCE" ~fortune cookie