Didn't future Hiro say that he stabbed Skylar and Skylar regenerated because he killed Claire at homecoming. Thus, future Hiro thought that if they saved the cheerleader, they would save the world, because then that stab through the heart would be fatal. So, in future Hiro's timelike, the stab is not fatal, in regular Hiro's timeline it might be.
Any thoughts on the fact that BOTH the Petrelli boys have powers and their father did not? Does this mean that their mother does, for there to be such a strong genetic link? Wonder what her power is. . . .hmmmm. It is also mighty suspicious that Papa Petrelli knew Lindermann and that his granddaughter Claire has a variation on a healing ability like Lindermann does, but inward focused instead of outward focused.
Oooh, an affair between Mama Petrelli and Linderman?? I like it!
As for whether Mama Petrelli has powers, she pretty much admitted that to Claire when she first met her. We just don't know which powers she has...should be an interesting few eps before the end of the season .