chances are very good that your race will still be wetsuit legal, because as far as I know even ponds around here (northeast) rarely go over 78. I would plan to be racing with one but if you can manage it do some open water swims with and without so you have a feel for the differences.

As for brands, I think it's whatever you feel best in. I ended up with a 2xu.
and for my one and only race so far (soon to change) I found it was much easier to pop out of at the transition than I'd feared/imagined. maybe because I'd practiced on bone dry land!