Cool stuff Griff
PHOENIX BIRTH
You may draft a Merciful Jean Grey figure. If you do, Phoenix does not start the game on the battlefield. A Merciful Jean Grey that you control
gains, and must use the Phoenix Fire special power, and if she is destroyed, switch her with Phoenix.
PHOENIX FIRE
Anytime
Phoenix a figure you control with this special power receives one or more wounds or is destroyed, one at a time, you must roll 1 unblockable attack die against each figure adjacent to her.
Not sure if those suggestions work. I just thought it would make it clear that Jean Grey has the power of Phoenix Fire when she's played in the same army as Phoenix. Also, Phoenix Fire referred to Phoenix, so it would sound kind of wonky if Jean Grey had the power that referred to Phoenix taking wounds, especially since Phoenix isn't in play.
I guess the only other thing is that with no special defense, her 5 defense and 4 lives doesn't seem to make her much more durable than normal JG, though Phoenix does have flying to give her better defense if there's any height available.