1 A trisuit, or tri shorts and a tight fitting top. By the way, i am a swimmer, and wetsuits are fine with me. kind of like wearing a fast suit... You might want to try fitting one, they should be pretty comfortable, and they save a lot of energy for the rest of the race. On the other hand 68 is pretty warm... (Try swimming in the SF Bay)
2. No. Just no. In T1 or T2 it is not logical to put on ANYTHING besides socks (maybe), shoes, a helmet, and a race belt. I would reccommend a bento box or similar item to hold nutrition and then transfer that to a jersey or mid bike, or leave it on your race belt for T2
3. No there is no rule about that, but it might be a good idea if you have the money. I did my first tri in running shoes and clips. T2 was very fast, but i have to say i prefer clipless.