Group Interview with Apple! Help!

So, I've been emailed by someone from Apple about a group interview at a Toronto hotel. I've replied, confirming my attendance at a particular time.

Wondering. Attire? I've always assumed business casual at the least, as the email also specified was the dress. I don't want to over do it, I don't want to under do it. Thinking a nice button-up shirt with a new pair of stylish jeans and dress shoes?

As for questions they'll be asking/situations they'll be putting us in... Does anyone have any tips? I'm guessing that they'll pair us off after an introduction and have us show our one on one skills (maybe Specialist or Genius specific, as the interview is for both).

Thanks in advance for any help.