So if the Hyatt hosted a wedding reception where alcohol was served, no minors could attend.
This is not similar to what got the Hyatt in Florida in trouble.
I'm not sure if your scenario is in a restaurant that also sells liquor, ballroom rented for private party, or a bar that sells just liquor, but I'm guessing (if your question is “can a minor enter?”) the answers are yes, yes, and no respectively.