No, there's no difference. And I don't think of it as a U.S./Canadian difference. "See you" or "see ya" is _very_ common in the United States as well. I think I'm more likely to say "see you" than "'bye" myself. If you really wanted to search for a literal meaning, "see you" is short for "I'll see you real soon," so it suggests a short parting and a reuniting. "Bye" is short for "goodbye," which--although nobody thinks of it consciously--is short for "God be with you," so it is wishing someone good luck and a safe trip. It isn't really talking about reuniting. Different people use different words of parting. It can be an expression of personality. For example, when saying goodbye to a young child, we are apt to say "Bye-bye!" or "B'bye!" So some adults say it, and it means they are projecting a spirit of playfulness or childishness.

Not really. They both mean the same thing.

it's about culture i guess. but it mean the same thing