Sorry to hear of your mobility issues; have mobility issues of my own. Again, please change Abraham P. Riggs' middle name spelling.It is not Pearce but Pearse, this by his own hand.
Happy to hear of more lines. I am very curious about Sir Ambrose Riggs as he was with Penn's bunch, land holder in Colonial Maryland, and also listed on one of the first or second ships to the Carolinas...carried as Gentleman, not with an occupation. I did find out about an Ambrose Riggs in the 1600s who was born in Westmoreland County, England and was disowned by his father, a Church of England minister in same county, because Ambrose heard George Fox preach ~1650 and became a dissenter/Quaker and blew the father's plans for him to follow in his footsteps. He is more closely associated and in fact heir of George Fox the Younger, a different preacher. This Ambrose has a brother named Anthony Riggs however I have not found the father and mother's name yet there was mention of chambermaids, so servants, in Ambrose's bio. Ambrose married in now Sussex County, had 5 children live, and presumably died there and is buried at a Quaker house of meeting.
Difficult to believe the two are one and the same man so I will continue to persevere research as two men named Ambrose Riggs.
Do keep in touch David, as you are an old friend as well as kin.