I'm not a big fan of either name.
Ethan has always sounded a bit pretentious and immature to me, and right now it's terribly popular.
Elle is very nickname-y to me, and not attractive either. I also don't care for giving twins or siblings the same initials (or even using the same first initial for both). And I especially don't like using a form of the same name for each one's mn.
~
Heather~
