1. I'm not familiar with the Hydrothruster fittings but... Are the holes threaded? If so, you can pick up some threaded plastic barbs to screw in there at Home Depot, with some teflon tape to seal it.
2. The de facto standard currently is Tygon(
http://becooling.safeshopper.com/28/164.htm?805 ) tubing, but it is quite expensive. Supposedly Clearflex(
http://www.cooltechnica.com/Merchant...ategory_Code=H ) is just as good, but significantly cheaper.
3. Reservoirs... seem so simple, but a lot of people have different views on what they should be. I believe they should be a low pressure area connected to the pump intake where the pump can suck water from without much restriction. Also, they should be able to trap air from the coolant loop quickly. If you run your pump continuously, it doesn't matter physically where it is located, but if not, it is best to have a part of the reservoir occupying the highest point in the system. A res should also have a fill point.