I have Martha Ivany as the granddaughter of George & Margaret Ivany and James Pottle (wife unknown). The problem is that there were two James Ivanys----one from Bonaventure who married Matthew Abbott's daughter, Joan---and another from English Harbour, who married James Pottle's daughter, Joan.
I frequently see these two Joans mixed up in genealogies that others have assembled, and this may be the root of your information.
I have traced these names back to source documents, so I am pretty confident I have it right, but please let me know if after reviewing your records you continue to hold to your position that Martha descends from Matthew Abbott.
You are right that there doesn't appear to be a connection between Matthew Abbot and the Abbot families of Bonavista.