1) What should the layout of the reactor's shell be?
a) How many fluid ports do I need/should I use?
b) What other parts would I need? (ie. steam generators/ liquid heat exchangers, etc)
It has been a long time since I last played Minecraft (or at least the IC2 part of it, I'm a big fan of technical minecraft), so I might not remember things correctly. Anyway, I'll try my best to answer your questions.
1. Depending on your needs. You can put the access hatch, redstone port, fluid ports wherever you like as long as you can get all the (hot) coolant in/out.
a) If you just put 1 ejector upgrade inside a single port, 15 is needed.
b) This is highly flexible. You can use the heat to generate biogas, steam, superheated steam, or directly into EU via the stirling generator. There might be more options that I can't remember but more info is available on the wiki and here. Each one has its own pros and cons, which is up to you to decide.