I'll try again,

To Private Schweik,

I have no doubt at all that Leslie Riddle helped A.P Carter in his collecting and undoubtedly the Carters would have learned songs from him. However, in the pieces you posted above they state that A.P met Leslie Riddle in 1927 and 1928. As the Carters first recording sessions were in 1927 and Maybelle was already no slouch on the guitar I feel that Leslie's influence was more on the material that the group sang rather than on Maybelle's picking style.
I shall have to listen to Riddle's recordings again to see how close their styles were or were not.

Hoot.