He's called Ed-E because of his license plate, not because of the type of bot he is.
Yeah there is that too. But it does also stand for Eyebot-Duraframe subject E. Listen to what it says when you repair it.
Anyway I'd probably pronounce it ee-dee-ee. That's the way my brain wants to say it for some reason. I know for I fact that I'd have an easier time just calling it Eddy lol. It doesn't matter to me though. I can honestly say that I've never said it's name out loud, and I doubt I'll ever have to.