I normally have the philosophy that anything goes as a middle name, and you're right--Ganymede the myth did come first. I urge you to abandon this one, though. Ganymede is more than just the root of catamite. It's slang used by pedophiles for the boys they victimize. They're very fond of the name. You can google it and find the Ganymede Collective in Montreal, Ganymede vacations bound for brothels of little boys...it's just a big big yuck. The myth isn't cute enough to balance out this ugliness.