I'm pretty sure its too late to enroll for ISAC, especially since classes start tomorrow (Thursday). SMSPP won't start until June 20. You'll have to contact Dave Hacker to see if its too late to enroll. Both programs are really good, I think. I did ISAC, and it was great.
No official dress code for class, but of course they strongly encourage you to dress appropriately. The administration doesn't like to see miniskirts or shirts showing stomach, etc. You know all this by now. For OMM, you gotta wear shorts and T shirts. For girls, they ask that you wear sports bras too cuz you gotta show as much skin as possible for palpation. Guys have to take off their shirts. For anatomy, pretty much its up to you. But remember, whatever you wear will smell like embalming fluids, so I suggest scrubs or old clothes you don't mind throwing away later on. The school provides lab coats.
Hope that helped. Enjoy the remaining summer, and see you all in the fall!