So the jury is IMO out. Because of the American town name, we may include Memphis here.
Thanks to Michael Tilgner for pointing me at Morenz' opinion, and at Sethe's opinion see References below. Apparantly the region was called after the product it was famous for, and there's thus a clear Egyptian connection.
A label including this name was assimilated by the Arabs to their own language as Abul-Hol which means "Father of Terror" in Arabic. I'm not convinced untill someone shows me an AE text mentioning a pehemu used for example to refer to a hippopotamus.
In that case the final Hebrew form would merely have been influenced by the native and similar looking behemah, so a sort of popular etymology being done on the Egyptian loan-word.
Plutarch, in Manetho Fr.
Gardiner p. AD, and in reality i.