Walt's Powers?

No we didn't, but whenever he was ignored and wanted attention, something happended that he thought of.

Walt has the ability to make things happen similarly to Carrie. He has the ability to appear suddenly in remote places and to quickly disappear from those places. He, on more than one occasion touched a character then read that character's future. He has the ability to understand when the island needs help to survive. He can see and hear dead people. He was born with a negative force inside of him but with encouragement that negative force has morphed into a positive force for good.