We have spoke in the past concerning your ancestor Ross.I must clear up what you wrote here for others, as you have the family mixed up.
Esther Shelby , daughter of Moses & Isabella Alexander Shelby, married John Carothers , nephew of Hugh & Sarah Pruviance Carruthers . John Carothers is the son of James b. 1718 Pa, d. 1763 Ire , Jim sent 4 children to Hugh's twin (John) in Pa, in 1764 , The Carruthers brothers (all 4) moved to of brother Jim's sons to NC, (Andrew & John)
The Alexander connection is mainly in Hugh's older brother William's lineof Augusta Va.
The Polk connection is in Hugh's twin brothers line , that of John & Sarah Neely Carruthers and nephew John Carothers line. Hugh was close freind of Thomas Polk Atty.Moses Shelby's brother Rees's daughter Mary is married to Thomas Polk Atty., Moses's sister Esther is married to John Polk, 1st cousin line to Thomas Polk. The Knox connection is again that of his twins line.
Purviance:on this is Sarah's brother John line he married Marg McKnight .
Concerning Carruthers: We arrived in 1669 Pa. around 1740 William & Hugh Carruthers moved to Augusta Va, Bill settled on the Bordan grant, Hugh southwest of the grant. And here is most of the NC families (Allies) you have come across in NC. In 1764 Pa is were you can start to place and put together the Carruthers siblings, for those of us that went into TN, the relations is seen easly, as is the Allies Alexander, Graham,Knox,Polk,Gillespie,Irwin ,Shelby,Williamson .
I am sorry to say I have not spent much time on your surname "Ross" , reason for this is the 1st connection found to Ross is at Esther Carruthers .
I hope this helps. As I fully understand the confusion in the Carruthers lines, and it is all of one Carruthers family line .