Board Thread:Questions and Answers/@comment-108.204.144.54-20131228001817/@comment-213.140.59.148-20141221213150

It's spelled Euphy in the canon. Or so does Nunnally write it down on the candle in Turn 8. That is why I see this spelling as the most correct for this character.

In a most general way of spelling nicknames, I guess it works both ways as already said.