You are aware that not all the jews left Spain. In fact, some analysts say more Jews stayed in Spain and "converted to Christianity" than left Spain.
Their culture and knowledge didn't just disappear in 1492. We are talking about 1 or 2 generations into the discovery and re-settlement of Mexico, and there should have been plenty of people who'd learned Hebrew at home in Spain out there wandering about looking for all the world like any other Spanish caballero ~ horse and all.
By 1600 the Spanish had effective control of just about everything they'd ever heard about or seen in North America ~ so you'd had educated people leaving their marks.
yeah, I know.
I have to listen to this stuff all the time from my friend who is Jewish and of Spanish and Moorish descent.
We discuss the histories of where they went, how they assimilated publicly but acted privately.
We discover some pretty amazing stuff.
Luv history.