It is very wise to admit you don't have a clue, however I think you do yourself down. Clearly if you have managed to Root your stock ICS you have at least a grasp of what your doing.
I thoroughly recommend the various "dummies guides" for various topics, they taught me what I know from scatch. Yes the threads are pretty long, but a thorough understanding of what you are doing can be had from them. Reading them will answer many of your questions and possibly save you a lot of angst avoiding pit falls.
As for JB yes you can flash it, be aware that ICS kernels will not work with JB and that Samsung have yet to release an official JB ROM fof the SGS2. What we currently have is a leaked stock version that works well and several "cooked" versions of it (the best being Neat, IMHO) along with more "exotic" versions ported and cooked for the SGS2. I recommend sticking to a Samsung stock based ROM.
