Thea, definitely. I knew a Theodora born a couple of years ago. Her parents called her Teddy, which I'm not a fan of, but Dora is a lovely nn too.
Amelie is ok, it's quite sweet. I think it sounds much nicer with a French accent and loses something over here... it's a bit too 'girly' for me and will merge with the Amelias / Emelias.