OK - that's the "Noah Sharp" rifle with the buzzard head patchbox. I love that rifle - it was one of the group on display at Abingdon that fall. The "JW" rifle in Jerry's book is the one that he describes as "an east tennessee rifle with fine architecture" - it was also shown in his Muzzle Blasts article years ago.
One thing I have learned about these southern gunsmiths - never say never - some of them worked a real long time, moved around a whole lot, and made a range of styles depending on the time, place and customers. So your observation regarding the cheek piece initials may indicate a new clue, a link or something not readily apparent by looking at the styles.
I don't know if anyone knows the answers to your questions for sure. On your first, if I had to go on just the styles, I feel they were two different makers as they are pretty radically different styles and pretty far apart in age. The JW gun in Jerry's book appears to post-date the "Noah Sharp" gun, probably by 30 to 40 years.
If the Noah Sharp rifle is not from Botetourt or farther down into SW Virginia, I would guess it to be from the Cumberland Plateau/Middle Tennessee or perhaps even central Kentucky. Noah Sharp is pretty well nailed down as to time and place in Kentucky in the 1790s and he was not a gunsmith apparently, and he came from Virginia. Wallace speculated in the article that Noah could have obtained it while in Virginia before leaving or on a return visit in the 1790s, but also doesn't rule out that it could have been made farther west. It really looks to have strong ties to the work of Jacob Young and some gunsmiths working around middle Tennessee and Kentucky by the 1790s - to me it has a real similar feel to it as the Whitley gun - and in my opinion could have been obtained right there in Kentucky or Tennessee. The reused barrel, to me anyway, sort of lends itself to the concept of the type of work some early gunsmiths in the region might be doing.
Good luck
Guy