I was also thinking of an elf-like human replacer. Maybe a bit shorter then humans but not like dwarves. Going with this I might take away elves and dwarves and have some of their traits represented by other races. These human replaces can also come in all shapes and sizes, think Waluigi and Wario, so there can be interesting customization on appearance in a slight cartoony fashion. However, most will be the default human look.

Maybe for the names of the races and elements it could be based on the language of their world but have context clues what you are talking about based on the sound. For example, Ferea would be fire.