The EA-18 will start being delievered in 2007 and will deploy in 2009, that is the plan right now. If you know anything about government procurement, I would not be suprised if that slipped a little to the right. In that 2 year time they will stand up the RAG and start training crews. The complete change from EA-6B to EA-18 is suppose to be done in 2012.
As for the name, there was a lot of grumbling in VAQ because of "scatological connotations" as it was delicately put by Navy Times. They had a panel of guys from the RAG to come up with suggestions for a new name, Mongoose was a popular one (associated with the Wild Weasel Hunter-killer role). And as for the designation, I have yet to see anything definitive, whether it is EA-18A, EA-18G, who knows?
Can the EA-18 do everything a Prowler does? No, but it can do a lot of things the Prowler doesn't do now. The addition of hard kill weapons (JDAM, JASSM?) is being looked at and a new platform is really nice. Losing the 2 extra guys is not good, but they are not making a 4 seat jet anymore. I think it will be a slight loss in capability but not too bad with all the computerization. It definitely won't be as big a loss in capability as going from the F-4G Wild Weasel to the F-16CJ, that was a real big loss.
Finally, the Prowler is pretty hard to land at the boat. They apparently used to send guys with pretty good boat grades to VAQ if they were just OK in ACM, at least that is what the pilots told me. The two biggest reasons I think it is hard to land an EA-6B on the boat is it's size and the lack of gucci gear, like a HUD. I am an ECMO from one of the land based squadrons so a pilot (we don't have one as far as I know on the board) or EA6Bflyer could probably tell you a little more.