According to several sources, Catherine married more than once, her last husband being John Vaughan of Cefn bodig.
Catherine is not named in the Will of her husband John Vaughan, so presumably she died before he did. There is an entry in the Llanycil parish register which reads:
Catherine Vaughan alias Moris of Kefn Bodig was buried 22th of Aprill 1659.
If this was her, then it is possible that Moris (Morris) was her surname from an earlier marriage. However, it should be noted that in the register for this period, the names of women who died before their husbands were shown along with the names of their husbands (e.g. from the same page in the register: Jane the wife of Griffith ap Evan of Bala; Elizabeth vch Evan the wife of Robert Thomas of Lloddie; Agnes Antony the wife of John Morgan of Bala, &c). In other words, there is no reason to assume that Catherine Vaughan who died in 1659 was the wife of John Vaughan of Cefn bodig.