Thanks for publishing such great notes on the Perrins. I'm working on the Farmer connections to the Perrins in early Henrico.
Regarding Thomas's and Ann's children, could there be another, or is that asking too much...Research has suggested the following even though I don't have any direct sources.
A=>Henry Farmer b1657 married c1680 to a dau (Mary?) of Thomas and Ann Perrin. In 1688 they bought land at Proctors Creek. She died before 1695 and Henry married 2nd Widow Hester Bass nee Craddock. (I've looked at all of Henry's neighbors and Thomas and Ann are the only ones that make sense as in-laws.)
B=>Frances Farmer married 1)Richard Perrin ()who died bef 1688 2) Martin Elam who died 1695 3)Francis Patram. (Frances had Anne Epes witness one of her deeds. Anne is an aunt to Richard Perrin's children but she is also an aunt to the Farmers.)
C=>John Farrar son of Katherine Perrin married c1720 to a dau of Henry Farmer.(This is on the web, but I've found no source.)