Eh. It’s a mannered debate about the plural of “octopus”. Honestly, I think fretting about whether the root is Latin or Greek and the ending of the plural form matches is a waste of time—we’re speaking English. What matters is that it is understood, and what the convention is. So let’s ask the scientists who study octo-whatsises!
Searching PubMed for the various forms of “octopus” gives the following numbers of references:
I’m sticking with octopuses, the form hallowed by informed usage. I won’t spit in your eye if you call them octopi. I suspect the only people who would call them octopedes are skulking about on the humanities side of campus.