Some of them made it through relatively intact, worst of the flanderization bat hit Akihiko, Chie, and Teddie... Everyone else is at least recognizable. I am however happy to say that Yukiko did get a fair share of scary moments.

Regarding the murders... (SPOILER) I do not recall the series giving a clear answer about the body disposal, or finding one on the wiki. At best I can offer the following theory. The TV world is a landscape greatly based on conscious thought, so it is unlikely that a thoughtless carcass can remain there for long. Dead bodies and other refuse are likely automatically ejected from the TV world after a certain time if they are left unclaimed by a sentient entity. I theorize being strung up on TV antennas to be a result of the antenna's connection to the world's medium, the television set.