Don't apologize for a massive post. Good questions, and ones that need to be looked at before venturing in to a very expensive field.
I'd check with HAI, as they keep pretty good statistics on this sort of thing.
The pool of suitable pilots is, in my view, quite shallow, and once the aviation business picks up, will rapidly become much more shallow. This is particularly true in the helicopter business. No detailed, rational basis for my view, except some discussions with operators.
Get a variety of types, and keep learning.
Is joining a military an option? Might be a cheaper way than paying for it yourself.