From the actual marriage bonds I have all of my bondsman have been family or friends of family. As for witness could be an official of the court, or family member or family friend. It all depends. You would have to get a copy of the actual bond and try to figure out through research how the bondman or witness may connect to your family.
Many libraries NC may own the Microfilm on the NC marriage bonds. I think the NC Archives charges $12 for each roll of film if you wanted to buy the film. If you live in NC, the archives will charge you $2 for a copy of one marriage. If you dont live in NC, the archives will charge you a $20 search fee and $2 for a copy of the record. Its cheaper to get the microfilm if you live out of state.
I dont actually have any orphan records in my direct family lines so I dont know how the bond process may have worked on those but someone else on this board might know.