I wouldn't worry about online, i'm pretty sure the mode will be available on the Wii U. As for the game, EA has confirmed that it is in development for the Wii U.
Yes it has online, but IIRC it was pretty hard to find a match last time I played. But the gameplay with pointer controls is superb, it's somewhat hard to get used to but when you master it, it's pretty hard to get back to normal football games, specially passing because it's incredibly precise. But the problem is that it is limited by wii hardware, some modes are left out, limited tricks, among other things.
That basically. I cannot play FIFA because of how well the Wii versions of PES played, it's like taking a major step backwards gameplay wise. Sadly each yearly update of it didn't really have much new in comparison.