Boys:
Eddard- Prefer
Edward.
Bran- I love this name, but not quite as much as
Bram.
Rickon- Eh. I mean, clearly referential but not horrible.
Jorah- I like it.
Janos- Usable but NMS.
Jaime- Usable but NMS.
Tyrion- I can't help but really like Tyrion.
Joffrey- Usable as
Geoffrey.
Tommen- No.
Renly- Well, it's pleasant sounding but I still think no.
Stannis- No.
Theon- I like Theon.
Rodrik- Eh.
Arryn- Not spelled this way.
Tywin- No.
Sandor- Another name I like.
Samwell- No.
Jory- It's cute, I think of it more as a nickname.
Girls:
Catelyn- However it's pronounced I think it's totally usable.
Sansa- It has a nice sound but, again, clearly referential.
Arya- I like
Arya and
Aria.
Daenerys- I hated this name until I actually met(!) a little girl with the name Daenerys. Instantly fell in love. So I totally think it's usable.
Cersei- I think this spelling is crap, and also the character.
Brienne- Usable but NMS.
Osha- No.
Yara- No.
To add: I do like
Asha.