Total cost of my Mod fATPL was around £55k, though theres a bit of fat in that.
The rumours at the moment are that theres a bit of a shartage of instructors. I might have thought that if you were to discuss your ideas with a few flying schools they might help out. A friend of mine who recently completed fATPL mod was offered an FI job; they pay for the FI rating, and he is bonded for 2 years.
I'm not an FI, so could well be wrong, but I don't think you need an fATPL to instruct; a CPL with FI rating should do? The multi IR is the expensive bit, so financially it might make sense to get a PPL, CPL and FI, then do the MEIR while instructing PPL's?
Good luck whatever you decide!
OL