OK, I'll try to answer your questions. Just so you know, I have a CPL(H) and nearly 300 rotary hours, and I'm about to start an instructors course. I also have a PPL(A) and nearly 200 f/w hours. I'm an...er...older-than-average wannabe, hoping for a bit of part time paid flying, and I''ve managed nearly the whole thing without any debts. But I've been around a while and talked to people and learned a bit, so here goes....
1) Career opportunities. With a CPL(H) and low hours, not a lot, at least in the UK. But that probably applies to f/w as well. Until recently you could get a left hand seat on the North Sea, build up your hours, then go for things like the police, SAR etc. 9/11 meant that the dual qualified airline pilots who'd been laid off went back to the North Sea, and the companies there are now asking for at least an IR, which will cost you around £23,000. And I'm not sure if they'll guarantee you a job even then. Most people are getting 300 rotary hours and an FI rating, and then...? See what happens I think.
2) Salaries. There are people here who know a lot more than I do. But one thing is certain - no helo flying pays as well as the airlines. I think First Officers on the North Sea are getting around £30,000, if you can get there. Instructing pays better - around £40/hr, but you tend to do less hours than in f/w. Anything else I don't know.
3) Training Schools. Ask around when you start, and keep asking. I have no connection with PLH Associates, and I've heard some good things about them from people who've used them, but it will cost you and I don't know if it's worth it - you can find out most of the info yourself.
4) Pros and cons of helos. Only one big pro - helicopter flying is totally wonderful, tremendous fun, ridiculously addictive, and...I love it. Apart from that it pays less, has no equivalent of nice comfortable well paid airline flying, jobs tend to be hard and dirty and uncomfortable and dangerous. In fact there's nothing in its favour...unless you love helicopter flying. Try it and see. If you do, that's what you'll go for. If you don't, forget the whole idea and have a nice comfortable airline career.
5) Achieve with a CPL(H)? I think I've answered that above. Well...total bankruptcy perhaps???
I hope some of that helps. Hopefully you'll get some of the more experienced people answering you as well as bickering among themselves - you never know; miracles happen even on Rotorheads.