Yeah, he's dead for good, though both Peter and Sylar have his power. The show did mention Linderman once, in a reference to a law, called the Linderman law. Though it didn't specify what the law was about, I imagine it had to do with the registration of all people with powers.
If you've been following the graphic novels, you'd know that there have been people with special powers since at least the Vietnam War, and probably longer. What's interesting to know is that there had not been a huge outbreak, nor widespread knowledge of people with special abilities, until this five years in the future, wear it seems like an everyday occurrence. I was a bit surprised about the kid that sucked all the oxygen out of the air in this episode. Just hearing about it made me wonder what good that could do. I suppose he'd be a pretty awesome fire-fighter.