Villa wouldn't have a problem with Messi, but I'm not sure if the 3 could start together. Messi, Villa and Silva, for example, would work better in my opinion.
Either Ibra or Villa in the same team. Villa would be more more effective down the middle, rather than playing on the left, with Ibra in the middle, if you get what I mean? So you would have to start one of the other, in the formation Barcelona play. It could work, but Villa might not work well in that specific role.
I would love for him to join Barcelona though, Villa would be my number one signing.