In Canada, only 50% of your second in command time will count as total time towards your ATR or ATP. Two exams, the INRAT, and a MET/NAV.exam count as the ATP written. Much harder than the FAA equivalent, but realistic.
As for hiring Americans, as long as you have the right to live and work in Canada, anything goes.
Good luck, Air Canada is financialy stable, or at least somewhat in an unstable time, and have nice equipment. No labour issues which is also a bonus.