The John Kelly who married Susannah Arthur died in 1751.

From familysearch index:

**********
Other information in the record of John Kelly
from Isle of Man Parish Registers
Name John Kelly
Event Type Burial
Event Date 16 Oct 1751
Event Place Marown, Isle of Man

******
I’ve just trawled through wills on familysearch and found that this John Kelly named his brothers in law as William Arthure and John Arthure.

To view the will image, use this link:

www.familysearch.org/search/catalog/234410?availability=Family%20History%20Library

*******
Scroll down to film 106379 and click on the photo icon.

There are 1081 images. Click on the image number box and change the number 1 to 974, then enter. Then keep clicking on the + and it will zoom you in to John Kelly’s will. I reckon that this shows that Susannah Kelly alias Arthur, his widow, was a spinster when they married in 1739, not the Susannah Arthur nee Aspinall, widow of Hugh Arthur.

It still doesn’t help in knowing the name of Susannah, William and John Arthur’s parents. As Frances says, they could be a Malew family. Or perhaps they were born in Scotland (father Thomas, merchant) and that would explain why their baptisms don’t seem to appear in Manx records.

Jean C