Fascinating question, Robert, but for me it's a difficult one that gives me a headache, since it's not a way I categorize words as I come across them. Aspirin, perhaps?
I agree that it is a fascinating question, and I tried looking for hybrid words. I have searched in Google, on Wordcraft and some other word sites, but so far haven't found much. Now, interestingly, yesterday when I posted about homographs, the definition said that they have the same spelling, but different meanings and origins. Now, they aren't hybrids, but Tinman posted a list of them awhile ago.
I am going to continue to look, though, for the "hybrid" part!
Horticulture, I think that a Roman could figure that one out: the cultura hortorum, or some such. Hortus is Latin garden and cultura is the 'caring for, tilling of'. Anywho, homosexual is one of these Greco-Latin hybrids. Not so sure about astronaut. Latin nauta is a loanword from the Greek nautes. Latin has very few compound words, e.g., paterfamilias, but Greek, like its cousin Sanskrit, has many.