Good Morning on the east coast, and welcome to canreef. I can help a bit. The Bubble Magnus skimmer will have it's own pump.(plug and play, with some minor tuning) The Mag 9.5 should be ok for your overflow. I have a mag 12 on my 72 gal, and have to turn it down a bit, using a gate valve. Any/most plumbing parts can be found a Home Depot, or Rona. Unfortunatly my set up has a built in overflow, and i don't have a lot of experience with external overflows, but quite a few people on this board, have had great success with external oveflows. Good Luck, and have fun with it. It's a great hobby.
http://www.youtube.com/watch?v=-zVGwdRVHU4
This may help with the overflow.