I don't know if is legal buy and grow Peyote, about San Pedro I am sure that is legal (we have many sites in u.s where buy Tricho...)
about Mescal, to consume a Peyote will necessary 10 years, with a tricho from Growing 1/2 years are good to do a ceremony, and so Peyote is most potent I think, and thinking another time, illegal in u.s. (if you don't follow a determinate religion)
please my friend (I edited many of your post), edit your signature (I can't edit signature...), we can't have link of retailers/retreats..