I am interested in the Greenings of Devon although I can only trace my line back to an Edward Greening who married in Kelly in 1775. However I believe the line was descended from either William or Jasper Greening (brothers?) who migrated from Gloucester to North Devon, (Bideford area) in the early 1600s. The name is very common in Gloucestershire.
This couple, and their descendants, were traders and mariners - more than one was lost at sea - and as early as 1675 there is record of them sailing to and trading in Newfoundland. The forename Joseph is also found in a number of generations.
I know this gives you no answers but may add to your knowledge of the family - there is a strong possibility that they are linked. It will also keep the post current and possibly attract someone else's attention who may be able to add to it.