@Julie1258 Call Airbnb, and ask them to cancel this reservation for you, penalty-free, on the basis that the guest has already asked to bring more people than you can accommodate, keeps changing his story as to his intentions for staying at your place, and that he has outright lied to you about staying in Airbnbs "all the time", since he has not one review. tell them you feel highly uncomfortable with this booking.
I assume this was an Instant Book, or you wouldn't have accepted, right? I'm wondering why you don't have requirements of previous good reviews and recommendations if you're using IB?
No way I'd let this guy stay. Trust your intuition, it will almost always be right.