My experience with this (which is admittedly limited) is that at least in this part of Canada you could probably use "African-American" (referring to the continent rather than the country), "Black", or "African-Canadian", and none would be seen as inherently controversial, although most people would probably just say "Black" unless there's a reason to do otherwise. (For example, regardless of someone having black skin, "African-Canadian" would imply that the person or their family are relatively recent immigrants from the continent of Africa, and wouldn't be used to describe someone who immigrated from the Caribbean.)
Your tone and intent probably matters more than which of those terms you use, though.
As for something like "Seasons Greetings" vs "Happy Holidays" vs "Merry Christmas" - only someone who is looking for an excuse to be offended is going to care about that. ;)