Weren't the crew already doomed before WAU

[GhylTarvoke]

I don't believe Ross communicates with Simon telepathically, it's possible he is broadcasting messages to him electronically somehow, maybe both he and Simon have built in wireless communication devices.

That's what I meant. Not a mystical kind of telepathy, but one that takes advantage of Simon's roboticization.

Hmmm... that doesn't explain how Raleigh Herber can hear him.

As for why Ross can survive in the Abyss? Perhaps the WAU remade him in order to be able to do so

Interesting theory, especially since his body was found on the Climber.

Then again, the times that show him "teleporting" are the times in which he is briefly talking to Simon at Omicron and Tau, so maybe it's not him teleporting at all, but like you said, merely using his electromagnetic abilities to project his voice and an image of himself onto Simon's consciousness.

He doesn't always communicate with Simon when he's teleporting. (In the Abyss, for example.)