Definitely off my list events to do. Knowing how much training various people did and comparing that to assorted bike splits, there is no way I would ever make it around the bike course with enough time/energy to complete
This is a completely normal reaction for a first time ow swim. I'm quite happy swimming in open water now but will still take time after getting in to acclimatise to the water. Get in, let a little water in at the neck of the suit, stay as relaxed as possible and just tread water for a short time while you get your breathing under control. Breaststroke and/or float face down in the water for a few seconds. Wait until you're feeling relatively relaxed and in control before you actually start trying to crawl.
OW is much nicer than pool swimming once you overcome that initial shock
You'll likely need a full wet suit if you're looking at ow swimming in this country unless you is well 'ard!
Seem to remember that some places used to do weekend wetsuit hire but don't know if that's still an option. Many OW lakes have try before you buy suits available to hire for the session. Not sure how much they charge though.
You don't really need to spend much on kit initially. Yes, you'll need a wetsuit if you're going for an OW event but there are quite a few pool based sprint tri's around. Otherwise all you need a serviceable bike and helmet and, of course, running shoes.