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, and I will recheck my sources.
You are right that there doesn't appear to be a connection between Matthew Abbot and the Abbot families of Bonavista.