The second question...I don't know what to think anymore. Some people say it's online or splitscreen, some people say it's only splitscreen. The general consensus here changes every 12 seconds or so. --- I apologize for whatever I just said.
I'm pretty positive that it's no longer online, since Nintendo apparently doesn't like people being on teams. That's why they let HVS add a "Rivals" system. Thanks for trying to make gamers look even more antisocial, Nintendo.