Here's Parsons' and DeMattos' take on Claiborne and Ringo:
https://books.google.com/books?id=FxhgDwAAQBAJ&pg=PA45&dq=Ringo+Claiborne&hl=en&newbks=1&newbks_redir=0&sa=X&ved=2ahUKEwifl-qJvMDoAhUKS6wKHVOdBHQQ6AEwAXoECAMQAg#v=onepage&q=Ringo%20Claiborne&f=false
Except for the 1886 article I shared, all the accounts I was aware of that have Claiborne accusing Leslie of being Ringo's killer are from 1920's reminiscinces of old timers. I don't think there are any other contemporary accounts that report a particularly close relationship between Ringo and Claiborne. Based on the mid-eighties article I previously shared that named Ringo as one of Leslie's victims, it seems safe to say that at least some local people belived that, but how wide spread that suspicion was I can't say. Of course the source could have been loose talk by Buckskin himself or Henry Smith saying he had run into Leslie on the trail after seeing Ringo headed in the same direction.