Baldwim are trying to wind people up?
Unpaid staff certainly benefit flying school owners bottom line, but that's about it. Luckily there are few unpaid people around anymore(at least in my experience).
What makes you feel that someone who gets paid would be any less dedicated? Every instructor I've had the pleasure of teaching alongside has given as good a service as possible.
Most (PPL) instructors are so badly paid that they do it for the experience and the enjoyment. I treated it as an apprenticeship to start with and it has served me very well. I certainly don't think of instructing in an altruistic sense. It is a job, sometimes very difficult and occasionally frightening and as such all instructors should be renumerated. I know most students do it for fun, and just want to be in the air, but when you do it every day come rain or shine then you treat it in a very different way. Of couse it's a great job, but would I go back to full time? No way..
Good luck obs cop, you'll learn loads and hopefully have a brilliant time doing it. Get yourself unrestricted first and then think about add ons. A multi engine FI rating doesn't come into use that often at most schools though it may be useful to get it relatively early just because of the pre-entry requirements. I'm assuming you'll be doing an I/R on a twin.