Isn't it supposed to be a female form of
Elias rather than
Elliot, though?
I'm not sure if
Elliot is more acceptable on a girl, for me it's not remotely feminine (though I guess some parents think it's "omg!!!so kwool" to use unfeminine surnamey names on girls). I don't care much for Elliette, but it's better on a girl than
Elliot.