It seems that Sylar only removes the brains of people with powers. And if that is true, the family he murders in episode 1.5 had powers, and perhaps the little girl. Since the little girl somehow survived Sylar's attacks, maybe she will be a key to fighting him later.

First of all Sylar kills the chearleader. We see that in the drawing that the younger Petrelli paints, that the chearleader's skull is chopped off as well. So there is some association with him and chopping skulls and removing the brain.

Can it be implied that the family murdered in the last episode also had powers? And can the little girl be the key to fighting Sylar.
Sylar is obsessed with others with power, so it would seem outside the norm for him to kill some family for no reason besides his being crazy. In the last episode, one has to wonder why Sylar couldn't find the little girl especially with his ability to find her later this episode. She could have had some ability to protect her.
Also, since powers seem to be genetic, her family most likely had powers. Her mother's head was left in tact, but her father's brain was taken. Also, he was frozen solid. We have not seen any other freezing powers from any other character. From the police discussions freezing would be uncharacteristic of Sylar since all other murders were done with household objects. So this should be an ability of the father.

Since the father had powers, and the little girl was able to survive his attacks, do you think she has some ability to somehow protect her from Sylar's Attacks?