Is there a gold penalty on out of house cards I play as duplicates?
I built a Bara Nights Watch and I want to use my Jon Snow (Stark) as a dupe on my no-house Jon Snow.

Thanks.

Duplicates don't cost gold at all whatsoever. They don't have a house affiliation, title, text box, icons, crests, etc so it won't matter which house the card belongs to for attaching as duplicates.