My daughter will be 17 on 12/27. We've always separated Christmas from birthday.
I'd never personally have a registry list anywhere.
We've always kept her birthday separate.
Because your daughter has a 12/25 birthday, I'd still keep it separate.
In earlier years, daughter had so many gifts that we sent the thank you's promptly but also held back many gifts she was given and over the year as she needed and wanted new things, we brought out things that were her's.
I'm not one for registry things, that just seems like an invoice to me. Our daughter is appreciative of what she does receive.
My only irk... I completely separate Christmas and birthday... The wrap, room decor, everything.
A " half birthday" is non existent to us... You do it right on their day and you are great.
We've never had issues with attendees at parties on 12/27. Formal and informal. Most parents were ready for a break!