My ancestors also include Robert Pill (b 1685) son of John (b 1654).
You mention 3 sons in a post but I have Robert also.
Does this match your latest info ?
Five generations later I have Sarah (Sally) Pill married to William Borlase, whose son John migrated to Australia where his daughter Grace married William Lewis Mead and his daughter Sara Elizabeth married William Taylor and his daughter Grace was my mother.
I have about 300 Pill listed in my database if you would like to compare data - Graeme Dickason