Hello Marco
I will try and answer your question as best as I can. Its been a while since I last sat right seat in a 172 but I think Im still current
1) Canada has its own licence issued by Transport Canada,
Transport Canada - Transports Canada. It is ICAO recognized but not directly transferable to the JAR licence (mind you I dont think the FAA one is either)
2) Depends on the plane, but for single engine in the Toronto area you will be looking at around the $160+ mark for a C172, around $300 for a light twin (again depending on type). Something like a 152, 150 or Katana may be cheaper, but then there is only so much you can do with friends in a two-seater...
3) Time is dependant upon your finances and weather. I did my PPL in a 6 week consolodated course, and most CPLs are offered in the area of 12 - 18 months. The biggest thing though is money - if you can afford to fly 2 or more hours a day then you will be done in around 5 months all told.
4) Jobs are hard to get for the new pilot here in Canada. When you graduate with 200 or so hours, fresh commercial, maybe a MEIFR you will be one of hundreds (just like back home). Your best bet is to still work the ramp for a year somewhere rather than sending out a billion resumes hoping someone will hire you. Otherwise, go instruct until you hit the magic 1000 hour mark (dont let anyone tell you 500 hours will get you a job right away...it wont) and then go searching for a twin job.