not really a club guy so i couldn't tell you much on that.
Montreal if you're just visiting you can get by just speaking english but if you plan to move here, it would be a good idea to learn some french. as far as black people, there's a decent amount. haitians (french speaking, i'm haitian myself), africans (mostly from french speaking countries) and carribean (mostly english), but not many african-americans. i keep hearing from outsiders that girls from here are friendly as fukk.
french canadian chicks are cool all things considered. i don't interact with white people that much but a lot of them seem like hippies to me. asians from china are pretty much

while the darker asians (vietnam, cambodia, laos, etc) fukk with everybody.
being black over here is not much of an advantage or disadvantage as far as getting chicks. matter of fact, you'll probably get more play off the fact you're a visitor from america (as long as you don't overplay that card to the point of sounding like a dbag).