I don't even think these characters have pointy ears. "Elf" just means "faerie," in Elizabethan times, but I'd be co-opting it as a way of distinguishing a particular type of faerie that I don't otherwise have a name for.

I think the phonetic approach to the accent works semi-okay when (as in Harry Potter and the Goblet of Fire) the overall tone is humorous. But in a serious context, it's just distracting.