There is a place over in England connected to this name, that being the Earls of Sefton which was the Molyneux family, so why is Jane shown carrying this last name when it has not been proven she is a member of said family?
I do relize that place names was used as last names,
Sefton is a village and civil parish in the Metropolitan Borough of Sefton in Merseyside, England
The Parish Church of St Helen (Church of England) - the only Grade I listed building in the Borough - was first built around 1170 as the private chapel of the Molyneux family.
There is plenty on this family and area online! We need to find out the why and how Jane was associated with this family in the first place.