Needed to point this out
Im 99.9% sure that there is no difference between ENA and ƎNA.
In none of the titles of the webseries episodes, trailers, or dream bbq subtitles ever refer to ENA with the backwards E that the drawn titles have.
This leads me to the conclusion that her name. Across all incarnations. Is "ƎNA".
There is no difference, they use the regular E for convenience.