So http://thepeerage.com/p39239.htm#i392382 which is Burke’s based had Hugh Fraser, 1st Lord Fraser of Lovat parents as Hugh & Janet.
But The Scots Peerage, which is a more modern, accurate and cited source, doesn’t show this Hugh Fraser, 8th of Lovat at all, and expresses skepticism at the existence of Janet Dunbar.
The source, MacKenzie, Alexander. "History of the Frasers of Lovat, with Genealogies of the Principal Families of the Name to which is Added Those of Dunballoch and Phopachy", Inverness: A & W Mackenzie,1896, Archive.org, p. 57, https://archive.org/details/historyoffrasers00mackuoft/page/57/mode... has a much bigger family, doesn’t seem to have Thomas, and doesn’t cite their work. I’m not sure how reliable this source is.
The most recent source from Clan Fraser follows The Scots Peerage with an addition of two sons for Hugh, 1st Lord Lovat, rather than only one in TSP.
I guess the next step is to prune extra children.