Hi Gary. Sorry for the slow reply. I am working my way through your notes and I believe you are correct about Isabella. My information was not based on my own research (shame on me), but on a Pringle relation who has been reliable until now.
I would be delighted if you would are able to find the Pringle/Cowper line and send it to me. My email address is firstname.lastname@example.org
I have a lot more research to do yet and am particularly interested in tracing my husband's Pringle line back to the border reivers and Clan Pringle. My husband is a direct descendant of the Pringles in Northumberland, but, having had his Y-DNA tested with FamilyTree, we were shocked as he has almost no Pringle ancestors and he is an Irving/Irvine/Urwin with a few Armstrongs and Elliots thrown in. There were obviously some non-parental events!
Is your George Pringle related in any way to the border reivers or to my husband's Pringles?