1) Take it easy. As mentioned many times whenever this question comes up (which seems to be this time of year - everyone is so excited to get started! haha), it's better to wait until you actually start class to refresh. Every prof is different and will have different things they want you to know, so there's no use memorizing a bunch of things now and then find out your anatomy teacher has a slightly different requirement (i.e. my anatomy prof in PT school wrote her own coursepack, so we didn't need an outside textbook. She had exactly what we needed to know in the book she gave us). Take the time off to enjoy yourself and do something fun, because life will be quite stressful when you get in the swing of things. If you insist on reviewing, stick to broad concepts. I wouldn't go audit a class, especially if they charge money for auditing. You should be fine reviewing on your own.
2) Definitely go sit in on a class if you can...if nothing else, it'll give you an idea about the methods of the instructors/pace of the course, you can see if most people are using notebooks or laptops or are given handouts, you can get a feel for the formality of it, etc. And it's a good chance to chat with current students for inside tips. You can then ask them your first question directly, since they are in the program you will be in. They can let you know what anatomy atlas they use in the program, etc., so if you decide to review you at least have the correct materials.
