I’m also AOW and I have done a few of the Cenotes south of Cancun MX really have no rules I believe the general PADI is min. two full 80 steel tanks on at min one diver per group prefer it be on someone that is cave certified would be best. I actually hired a private DM with cave cert. to go with me just as a safety thing. I like to come back out alive if you know what I mean. There is no place for error no place to come up for air, water is cold fresh water and there’s typically no fish to speak of. These were inland caves not far from the ocean coastline. I think there are others on the coastline. One last important thing have a very good light and a very good back up light. Without a light you are toast.
Have fun