I'm fairly certain which manager you get is pretty random
I've restarted a season a few times.
First time round, I got Stacy or Lita.
Second time I just got Sable
Third time I got Stacy or Veronica
(I stuck with Stacy in the end
)
I spose it could depend on how you perform in your first few matches, but I reckon it's just random. only thing I can prescribe is restarting a few times until you get her.