I love Joe, and pretty sure he will be able to play everything perfect by the tour start. He is one of my heroes!
However I am not sure if he was the best choice for the job. For example Pete Thorn's or Phil-X 's energy would be a better match IMHO. Joe is mallow, kind, polite, usually stands in one place (due to excessive wah usage in his music) and kind of hard to imagine him playing "I ain't talking about love" or "Jump", because he has a different vibe. He has the Joe vibe that we love.
Edit: Just like Steve Vai, Eric Johnson, Slash wouldn't have been a good match and not because they would not be able to play like Edward.