The short answer- if you must. The long answer- there will be an open bar and we want you to have a blast! We also don’t want anyone to miss out because they can’t find a babysitter.
If your invitation says “and Guest,” then yes, if not, we would prefer if it was just you.
Business Casual, please. But we want you to feel comfortable, so if those shoes are too high or that top button is too tight, let it all hang loose.