I think it is also twee and I wouldn't like to be part of a name set that appeared to be a bit of a joke. If you had a clutch of other children called Sophie and Thomas and Paul and Louise in between, it would be ok. But for just two, it seems a little bit cartoonish.
Pity, as I do like both names.
Slightly off topic, I was at a social event recently with a person with a very obviously Christmas-themed name. Upon learning the name, a member of the group said "so, you must have been born at Christmas time then?" A bit of a pause, followed by the response in a slightly embarrassed voice "no, actually I was born nine months after Christmas".