So after seeing Dr Strange, I'm guessing these are the rules for variants in the multivurse?
Peter Parker: are you a high schooler with dead parents? Kinda nerdy but with a good heart? Brown hair, brown eyes? Refuse to seek medical care after spider bites? Congrats, you're a Peter Parker!
Loki: You like knives and the colour green? Fuck it, you're a Loki. Gender? What gender? Doesn't matter. You're a Loki. Black, white, or blue? Don't care, still a Loki. Old? Young? Loki. Black, blond, ginger hair? Stick something shiny and vaguely pointy on it, BOOM, Loki. What's this? An alligator? You green? See above. Loki.
Dr Strange: Benedict Cumberbatch.