Jools Watsham gave Xeodrifter on Wii U a release date during his recent talk with Nintendo World Report. We can expect Xeodrifter to be blasting onto Wii U July 30th. Like stated before, the game will indeed have cross-buy. If you bought the game on 3DS, you’ll get the Wii U version no additional cost.
He also claims that the cross-buy download will count as a new purchase. I’m not sure what exactly that means now that Club Nintendo and the Digital Deluxe Program has ended but I’m going to guess that’s a good thing.