Honeyichigo
The manliest
But it still doesn't make sense as to why there would suddenly be a second Mewtwo. That's the whole point about Mewtwo's character: he's the only one of his kind. To just bring a look-alike out of a blue and call it a female without explaining why another Mewtwo exists doesn't fly well, it'll just make the plot-hole bigger.
They could always, like, gee I dunno, explain it in the movie?