I mean, it's a valid legal question but it arises after the end of a long chain of "assume that this nonsense bullshit happens first and Alberta separates." So it's kind of like asking physics questions about stuff going on in Narnia.
Personally, I am an Albertan who is staunchly opposed to separatism and have been actively working against it. If by some lunatic miracle the minority moron contingent actually manages to "win" and Alberta separates, I would expect to remain a Canadian citizen. I would reject and renounce any stupid "Alberta citizenship" the separatists tried to issue to me. If the Canadian government told me that it was revoking my Canadian citizenship as well then I guess I would conclude that the whole entire country had gone mad and who knows what I'd do then. It's like asking what I'd do if I discovered that everyone's secretly lizard people, it's such an insane scenario that it's impossible to predict details like that. Maybe I'd head to Hans Island so that I could cross the border to Denmark and seek asylum there.