My cousin sent me a copy of "The Fauntleroy Family" by Robert H. Fauntleroy in which he states, "During the restoration of Michelmarsh Church about 1896, two stone slabs were discovered which came from the tomb of Tristram Fauntleroy,... One of them shows his Fauntelroy coat of arms impaling that of Holt. This clearly proves that Tristram married a Holt, and not Joan Stourton, as has been stated in some accounts of the family." He goes on to say that Joan Holt was the daughter of John Holt, widow of Thomas Villiers. Tristram Fauntleroy & Joan Holt had two sons, Bryan and John.
I don't know whether this clearly proves anything, and it would certainly be reasonable for Tristram to marry twice, and even have more offspring. No birth dates from either Bryan or John given either...
Incidentally, there is a wonderful picture of Tristram Fauntleroy from a stained glass window at Michelmarsh Church. When I told my brother that it was his 11th g.grandfather, he said, "I thought there was a family resemblance." !!! Oh, my!!