Nobody Important,
the problem here is that you are assuming that all the information I am relating was not around when Sum Nung was alive, but it was! I have pointed out before that just because we in the West had very little information about the status quo in Fatsaan and Gongjaau - and apparently even do today - and the fact that one sided and even incorrect information is spread by zealous students means that this is fact. I can only encourage people to come to Fatsaan and examine things for themselves, talk to people here, and it will be clear that what is believed as "fact" is quite different. As long as one can just rely on stories and articles in English, one will have a very limited view on the Wing Chun scene in China, past and present.
Have you actually been to China to talk with the seniors here?
So what exactly is it you don't feel is verified?
That Sum Nung was YKS's only disciple? This is just his/his descendants words... This doesn't make it fact. SN's story was even questioned by Leung Ting more than 20 years ago when he found inconsistencies with his stories, because there were other accounts of certain things which matched up much better than what SN had claimed... So, it is not that everybody was quiet while SN was still around...
And no, all information about YKS does not come from SN, there is Leung Ngau, Yuen Jotong, Wong Jing, and (supposedly, Lam family) as well as others outside of the family, which told quite a different story than say SN... already ca. 1950 at least.
What exactly is it you have a problem with?
That Law Man Gong is listed as the teacher of Fok Bo Chuen? That is not new at all, just you apparently didn't know... You can go to numerous schools and check their lineage charts - and it is YKS and SN people both, they didn't just change that after SN died. Think about it, they are all YKS/SN guys, so how would changing this make them superior to... YKS/SN lineage? Doesn't make much sense, does it?
According to Yuen Chai.Wan's son, his father learnt many different martial.arts, besides Wing Chun, which was perfectly normal for masters of that time. So mixing stuff and then calling all of it Wing Chun - as an example - was a normal thing to do. Chu Chung Man did the same, learning different stuff and then just calling everything Weng Chun. This is one reason there is such a mess... Given that why is it unreasonable if neither this mysterious FBC and FSC were not "Wing Chun" guys? And that the Yuen brothers learnt this style much later? Just like Chan Wah Shun also learnt it rather late.
But as I have said earlier, the YKS and Yuen Chai Wan lineage is a huge enigma and Lots of things said and claimed simply don't add up.
Far too many stories and no proof of anything
I do not make any claims, I am just relating what information is found in Fatsaan and Gongjaau, it is not to blame.on me that what people say here doesn't match what you think, believe or say...
Let me give you an example, you claimed Ng Chun So taught a fourth form. But here, no one, who heard about Ng Chun So or learnt from him ever heard or learnt anything relating to a fourth form. You mention the "Chong Kuen", but this is actually called "Che Ching Kuen" (normally) and is from Leung Fuk Chor, the first teacher of Fohk Chiu, not the source you claimed. Yiu Chung Keung and his brothers teach it today because they have a special relationship to Fohk Chiu.
You said Ng Chun So.was not famous, but he was - by all accounts here. So what source do you have to make you think you know better than the Wing Chun community in Fatsaan?
Now, quite a bit what you say is very different than what information is available here, so I am very curious as to what your sources are and what evidence you have to believe that you can dismiss what the local people say?
You talk about scientific method and documentation, where is yours?
The problem foe Gong Fu is obviously that everything is oral transmission and a lot of the events are lost in the mists of time...
So like you, I believe that whatever the ancestors supposedly were, it doesn't change our respective arts, and the only tangible thing we have is the physical expression of the art which can reveal much more than stories - although some history can help identify sources and influences.