What you say makes sense. I have not come across a record of it but Abraham Redman could have married a Bentham before Sara(h) Balthrop. He was age 50 when he married Sara. Could a 17 yr old (or less) write a will?
Abraham Redman is mentioned in his father John Redman's will of 1612--John too was a draper. One of Abraham's apprentices was Thomas Claiborne brother of Col. William Claiborne who figures so prominently in the founding of VA and MD in the US. Another apprentice is mentioned in Abraham's will as a witness: Hugh Wingfield.
My notes regarding Francis Bentham--"The various branches of the Bentham family were descended from a common ancestor, Thomas Bentham (c.1513–1579), who was born at Sherburn in Yorkshire and became bishop of Coventry and Lichfield in 1559. The bishop's grandson, Francis Bentham (d. 1670), a draper from Stafford, migrated to London, and established the London branch of the family. Francis's son, Bryan (b. 1627), was Bentham's great-great-grandfather, and his son, also Bryan (b. 1657), was master of the Clothworkers' Company."
from Bentham, Jeremy (1748–1832), philosopher, jurist, and reformer by F. Rosen
http://www.oxforddnb.com/view/printable/2153Regarding Bryan Bentham, Uncle of Richard Redman:
"8 Bryan Bentham
Bryan Bentham was born about 1656/7. At the time of his marriage, the license dated 17 Mar 1680/1 calls him "Bryan Bentham, Jr of St Botolph's, clothworker" and aged "about 24". Bryan Bentham and Anne Gregory were the parents of Jeremiah Bentham baptised 1683 in that same parish. Bryan became Master of the Clothworkers' Company in 1693. One of this name was Churchwarden at St Botolph's in 1701. (Source) Secondary sources also call him a pawnbroker, who "lost money by the stop of the Exchequer in 1672", which is quite unlikely, as this one was only 15 years old. It's more likely that our Bryan was the son of yet another Bryan."
Ancestry of Jeremy Bentham-- 2012 by Will Johnson
https://sites.google.com/site/countyhistorian/ancestry-of-jeremy-benthamSo maybe Richard Redman's Uncle Bryan Bentham is the son of bishop Thomas Bentham? Bryan might be the father of the Francis Bentham mentioned as Richard's kinsman? Bryan b. 1627 would be a son of Francis Bentham, (Francis the kinsman to Richard Redman), and grandson of Bryan Bentham, "Uncle" to Richard Redman?