2 Questions, Can A Parent Check A Minor Into The Hotel, Without Being Present After Check In? And Is The Convention Center Within Walking Distance?

You are going to need to call them

Yes, a parent can check a minor into the hotel without being present after check in. However, all hotel policy must be adhered to and the adult is responsible for the guest room and the individuals in the guest room. Thank you.

I am not sure you can. Unless it's a convention of students. Call them.