Sir George Felbrigge - Sourcing / cleanup / MP effort needed

Comments in Simon’s profile:

He probably belongs to the cadet or "Tuttington" line of Felbrigges.

That is, if he isn't a fictitious doppelganger for Sir Simon Felbrigge, KG, who did NOT marry a "Catherine Mallory" - his second wife was Katherine Clifton, widow of Ralph Greene.

I'm coming up pretty empty on this guy. Sir Simon Felbrigge, KG is the well-known person of this name. The link at https://groups.google.com/forum/m/#!topic/soc.genealogy.medieval/eA... says that this Famous Simon was the cousin of the George Fellbrigg who married Margery Aspale (the putative parents of Questionable Simon).

Geni says that Famous Simon and George Fellbrigg are second cousins. I get the same connection as Geni when I compare https://gw.geneanet.org/lard?lang=en&n=de+felbrigg&oc=0&amp... with "Royal Descents".

The only information I'm finding on a Simon Fellbrigg born in 1396 is for a possibly fictitious son of Famous Simon. There's a link MyHeritage, which I can't view because I don't have a subscription: https://www.myheritage.com/names/simon_felbrigge These links also match him with Famous Simon:
https://www.flickr.com/photos/52219527@N00/36900272716
https://www.werelate.org/wiki/Person:Simon_Le_Bigod_(9)

More credible sources credit Famous Simon with having up to three daughters but no sons, for example: https://groups.google.com/forum/m/#!topic/soc.genealogy.medieval/eA...
https://www.wikitree.com/wiki/Felbrigg-8

This book gives Famous Simon a son named Simon born in 1405: https://books.google.com/books?id=FqZ2DwAAQBAJ&pg=PA313&lpg...

According to Geni, Questionable Simon is the father of 1425 Simon is the father of 1455 Roger Fellbrigg.

FamilySearch has a different line: Famous Simon is the father of 1405 Simon is the father of 1455 Roger Fellbrigge. There’s an obvious error because 1405 Simon dies before his marriage and the birth of his son: https://ancestors.familysearch.org/en/LHVM-ZZZ/simon-felbrigg-1405-...

I think the real question is “what is the ancestry of 1455 Roger Fellbrigg”. If you look at his son, there are good notes saying that the line descends to a family in New Hampshire. It also says that the line can’t be traced beyond the mid-1500s with any certainty, and doesn’t include anyone named Simon or Roger Fellbrigg in the family tree. Nycholas Fyllebrigge

Summary: I have seen no sources but Geni tying Questionable Simon to George Fellbrigg, or any documentation for his existence. The undocumented sources think that any Simon Fellbrigg who may have been born around this time is a son of Famous Simon. So if Questionable Simon exists at all, he’s got the wrong parents.

Actually, the real question is "what is the ancestry of Nycholas Fyllebrigge". He's reasonably well documented, but the Geni notes indicate that his parents are unknown, and I haven't seen a reliable-looking source that lists his parents.