All are awesome and most are possible.
Healer can easily be done. +1hp per sec
Telepathic could use some work. Nobody ever uses team chat and if they do, it's usually not important.
Locater isn't really possible.
Shape Shifter should work.
Radioactive should work.
Yep, I'm working on Healer right now. :3 It'll probably suck though, because I'm better at modeling.
And with the Locator, I was picturing that all players in the minigame have some sort of mod on them, that acts like a tracker. Each of those trackers are shown as red&blue dots on a grid that's shown on only the Locator playertype's screen. :)
And with the Telepathic, picture how much team chat would be happening in a TDM that had all these playertypes, that had to somehow work together as a team, combining all their talents. That's where the Telepathic would be some sort of "counter", informing their team of the enemies plans. <3 hehe.