I could be wrong, Vegas might be different. But I don't think shorts are appropriate if they specified biz casual. Khakis and a nice shirt are called for.
As for Emerils, wife and I have done several of his recipes and use a couple great spices he has. Her only request when we were in Vegas for the Super Bowl was to eat there. We went with IX Bender and his buddy Jon. While it was nice and I would certainly go back, it definitely left me pretty disappointed. Remember though, that my expectations were sky high.
Let us know if they throw you out