Looking at the Davies will of 1708 you will see that they have written, (badly), 'Esgairygors' ... all one word.
After this will entry, (see also the stroke of the line above it), they have used the word, 'Strygos' and then, in the Freeholders of 1760, it changes again to 'Sgrygos'.
We have seen, in our various searches, the accidental changes of almost all of the names of houses and farms in the area. I have seen six separate spellings for Ffos y Bleiddiaid alone, (now called simply, 'Ffos'). The link that you made between John Davies and Thomas Richards points to the same conclusion that they are referring to Esgair y Gors.
We don't have any positive link for the Rev. David Richards to my family but the same can be said for others in the tribe. How many David Richards were there living at Lledrod in the period 1725 to 1730, a few, but they were all relatives of mine. A Rev. David, with a son named Thomas points to a name and occupation lineage. Lack of docs to support anything in the 1700s seems to be the norm for our searches for individuals so Occam's razor comes into play. As you said on the Anglesey Forum once, "If it's not him, then who is he"?
Regards, Peter.