I didn't have time to check when I posted this tip, but I have since done so. In your WikiTree portraits of John Howland's brothers Arthur and Henry Howland, there are discussions of their associations with the Quakers. Arthur apparently remained a Quaker and moved to Marshfield, MA, along with other Quakers, where he remained until his death. A note says that five generations of his descendants continued to live on his farm. There is no mention of his descendants remaining Quakers. I didn't look up his descendants. It is less clear whether Henry persisted in Quakerism. After being punished and/or fined at least three times in Duxbury for "entertaining" Quakers and allowing them to hold meetings in his home, he seems to have been back in favor with his townsmen by 1668, when he was re-elected Surveyor of highways.
This is an interesting project, and I wish I were able to join in pursuing it.