The indoor tri I did was similiar. They ask you to enter your estimated swim time when you register and then people are seeded based on there time with the faster swimmers going first. We started 15 sec apart.

I have the Pearl Izumi Tri Shorts and I really like them, I think my top is Sugio.
I just squirt some water on my feet to wash off and dirt then put on my bike shoes. I don't use socks for the bike and I don't really try to dry off. You will dry off fairly quickly.

If you can practive switching lanes by pushing off the wall and going under the lane markers. The one I did we started in the deep end so switched lanes in the deep end as well.

Sharon