Have you thought of Divine Soul for tanking? Won’t help with fire damage but Aid, Death Ward, Cure Wounds, and Spirit Guardians all help a Sorc on the frontlines. Staying power is definitely my main concern with a frontline Sorc.

My only concern with FoP is it eats a feat spot, though that’s certainly a worthwhile cost for a character you’ll have fun playing.

It may also be worthwhile to emphasize AC (whether from Dex or Str) and Con over Cha, to help with staying power. Most fire spells will at least do half damage on a successful save, and the one or two point swing in DC won’t be such a difference as turning a few hits into misses and having some extra HPs per SR.