Welcome Gary! Where you are at is where I was when I got into Railpro. No real home layout of my own, just a club layout that used Digitrax.
To answer your questions:
1.) the CI-1 and HC-Sim (program on the computer that uses the CI-1) can do everything that a HC-2 can do. It is not dumbed down at all.
2.) Not sure I'm fully understanding this question, but if you're asking about how functions will show up on a DCC throttle when running Railpro in DCC mode, then the answer is that you control what functions are assigned to which DCC function. On the Railpro throttle (including HC-Sim) you have 16 function slots that you can make into whatever you want. While you are setting these up you can set which DCC function button they are mapped to (F4, F5, F6, etc). It is extremely easy to do.
3.) You're right on target with your thinking. Railpro can be used at home on your test track and at the club with no problem. I highly recommend getting a second locomotive module so you can test and enjoy the automatic load sharing. And I recommend testing out the load-sharing at the club using the CI-1 and laptop combo.
Let us know when you get started and if you have anymore questions!
-Kevin