James,
I'm not Gale, but found your message interesting since I'm a longtime Warren, Halifax & Granville Co.,NC researcher, and many of the families you mention were from those areas of North Carolina. In case you are interested, there is also more info on the Bullock/Hawkins connections at this link:

http://www.southern-style.com/hawkins.htm

and for more on the Hawkins:

http://freepages.genealogy.rootsweb.com/~markfreeman/hawkinva.html

Many of the Hawkins line from this area were Indian agents and probably did intermarry with the various tribes they represented, and some were known for the various slaves they set free, too. There is also an interesting study online about some of the other families you named in regards to their racial classification and I recall that Isham Scott's was one of the families that a lot of work is included in the works of Steven Pony Hill:

http://sciway3.net/clark/freemoors/TheTurksareIndianshb.htm

I don't know if you've seen any of the above before, but Hill's work seems quite extensive and is several chapters long, and is well-worth a look through since it also contains some documentation for the author's work.

Deloris