1. Yes, but you can't switch off the three stage builder stage, and on mine, you can't delete them, though the stages I've built haven't popped up on random yet.
4. Character customized taunts are much, much better.
3. Also, apparently, the rush has borked down all the online servers, including the with friends one, which is why nothing works. Another tip to slow down your issues is to turn off all other connections to the internet. When I figured this out, I was able to play someone in California with no visible lag, but there was still a button lag. It still was fun, though.