Most likely, Native Americans came in several “waves” and at different times. There is also the orign of the Patagonians that doesn’t fit the Siberia model. There seems a lot more to learn.
Absolutely.
I used to traipse all over this area...even climbing all over the Tulum ruins...you can no longer do that, BTW.
Anyway, if you ever go to Tulum, be sure to visit Coba, which is close by. I once stayed at the ClubMed there for $6.00 a day.