I have biodegradable sunscreen - it's Aloe Up. I found it on-line. Cost about $10 per 4 or 5 oz tube (too big for airline carry on). I bought a water sport variety (SPF 30) which goes on like Vaseline - very thick. I was out quite long, and ended up sunburnt anyway. I noticed that I wasn't leaving a grease slick when I was in the water, maybe that's how they'll know if you're wearing biodegradable.
There are no hair dryers, and you're actually not supposed to bring them, but we do anyway (gotta tame the tresses!). No mini bars in the cabins (at least not in the cheap ones!!) Can't help you with the beer prices or restaurant recommendations, sorry.
There will be 14 of us on the cruise (10 adults, 4 kids [16, 14, 10, 7]), and on 9/22 we will all be wearing terra cotta colored T-shirts. Please say hello if you happen to see us : )