Kevin, I did not know that you live in the UK, my niece and her husband will be moving to London in January from Singapore.
John (II) was born in Pennsylvania it looks like around Philadelphia to me from the families and occupations, more Irish names.Nancy was born in Tennessee, do not know which county maybe Stewart. I have not found siblings for John (II) yet, were usually from large families.I have a picture of Nancy with her living children just before her death. The family story has John (I) born possibly County Wexford, Ireland and married in England.
While living in Mississippi there was a friend who was also a Rossiter/Rosseter descendant.Hers were all from England and were Presbyterian ministers in CT.