A) Ironman races do not require a wetsuit.
B) They make tri shorts and trisuits that are for the entire race. DeSoto, Speedo, Louis Garneau, TYR, everybody makes them. They are made to swim, bike and run. The shorts have a minimal pad that isn't as wide to accomadate running as well as cycling. They are quick drying. Sock wise it's up to what you feel comfortable with. I have yet to find a pair of cycling shoes that feel ok to me without socks, so I put them on. (if you use socks roll them off your feet before the race so that you can just roll them over your wet feet, pulling them on like regular doesn't work so well!) Get some speed laces or similar for your running shoes, you just slide your foot in and yank (Yankz are another brand) the bungee type cords to tighten them, no tying laces. If you have any other questions feel free to pm me anytime.