This is a family legend that seems likely to be true.
Although we can’t be certain of the timing, Luke Mizell Jr. probably married sometime in the mid to late 1680s, at a time when he was still living on his father’s patent within a mile of Mathias Marriott. We know for certain he was married to someone named Elizabeth by January 1691 when she released her dower interest in several deeds, and that he was still married to her when he died in 1693. Luke was perhaps 33 years old when he died, and his widow must have been still relatively young herself with two small children to support. At some point during the administration of his estate, between 28 September 1693 and 3 January 1694, Elizabeth Mizell remarried to Robert Hill, who was a neighbor of both the Mizells and Marriotts. Elizabeth Hill was still alive and living in Surry whent Matthias Marriott made his will.
On 12 June 1707, Mathias Marriott made a will which mentions three children, including a daughter named Elizabeth Hill. By elimination, she seems most likely to have been the same person who was married to Luke Mizell and then to Robert Hill. The only other possibility is the wife of Sion Hill Jr., Robert Hill’s nephew –- but he was probably too young to have married any daughter of Mathias Marriott. (Sion Hill Jr. does not appear in the tithables until 1697, thus was not born until late 1680 or early 1681.) We know that Mathias Marriot was married to Alice Warren (born c1645 according to her deposition) sometime before 1670. It seems most plausible that Alice’s three children would have been born in the first 10-12 years of her marriage and before she reached her late 30s. In the case of the second daughter named in that will, Margaret Flake, that is clearly so. She had married Robert Flake Jr., who was only a year or two older than Luke Mizell, sometime around 1690 and seems likely to have been born around 1670.
In summary, the circumstantial evidence is that Luke MIzell Jr. probably was married to Elizabeth Marriott.