I think it might be MJ. I think, maybe her powers will evolve or something. Not sure though.
Here are the chances I predict, for each of your poll answers to be the new Firestar:
Liz Allen: 30%
Kitty Pyrde: 15% - I added this option
MJ: 45%
Other or newbie: 60%
Jessica Jones: 55% - I think she may be Firestar!