I love
Cordelia and
Theodore and I think they sound great as siblings. The only way the repeating "or" sound would be an issue is if you only called both by their formal names and never by nn's, but that's unlikely (btw, I love
Delia,
Cora,
Theo, and Ted/Teddy!). I prefer
Cordelia much more than
Anastasiya (way too many letters!) and even
Milena.
