I'm going to a university dance team clinic tomorrow. The actual audition is in April, but there's going to be a mock audition at the clinic. Should I still dress as I was going to the audition or can I wear something I usually wear to dance class? Also, I haven't done hip hop in a few years so I don't have shoes anymore. Is wearing a sneaker like converse acceptable to a college dance team or should i go get a new pair?

This is unfortunately too late to help you, but it may help someone in the future. Always dress as if it's a real audition. While this one doesn't count, you are making a first impression. That first impression can make or break the real audition. If they remember you as unprepared, you have to overcome that later. If they remember you as polished and prepped, you have already improved your score.

Now, I will add that if full hair and make up are expected, it is ok to tone it down mildly for a mock audition. I would also say the same if school colors are expected to be worn then it's ok to wear the same outfit in black or another solid, basic color.