I'd always thought that Quetzalcoatl being 'light and bearded' was a projection of rarity, not necessarily of Europeans (although Cortez certainly took advantage of it LOL!).
And ther were finding of alkaloids like coca and tobacco in some mummies from dynastic (not pre-dynastic) Egypt. I'd read a report on that, and the evidence for either coca and tobacco or a very similar analogue is pretty strong.
But I don't think that's ipso facto evidence for any sort of transmittal of building techniques from Egypt to Mesoamerica. I mean, the pyramid is the simplest way to build a large structure because of its inherent stability and simplicity. Whether a ziggurat or a stepped pyramid a la Tikal in Guatemals or even pyramids anywhere else, it's not unreasonable to say that they were simply the result of parallel, but independent, development.
For me, the give-away would be linguistics and writing. Certainly, if there were some transmission of building techniques from Egypt to Mesoamerica, there'd be loan-words from the "teachers" to the "students" (or vice versa) but I'm not aware of any. Also, given the logistics of building a temple or pyramid, it's surprising we don't see any Egyptian hieroglyphs which were so common in keeping track of such efforts by the great Project Managers of antiquity, like Imhotep. But again, we don't see any such like. Mayan and Aztec glyphs don't seem to have any corelation with any kind of Egyptian heiroglyphsl and the Inca quipu aren't related to anything, near as I can figure.
Anyhow, that's where I'm coming from. I can trace the Great Consonantal Shift and the Great Vowel Shift as our prototype language, IE, began to spread out. I assume there've been some sort of research in Mesoamerican paleolinguistics that traces the same thing (?), but I haven't a clue as to where to find the information! Hopefully, someday I will.