Is this St. Augustine Sanchez one of our family?

Recently, there was a posting on another blog, My Florida History, that featured the Rodriguez-Avero-Sanchez House at 52 St. George Street in St. Augustine

But who is this Juan Sanchez who died in 1801? He isn't in the records that I have collected. Is he from another Sanchez family?

Please comment. Correct me if I am wrong.