Thanks or getting in touch and describing your researches into the Rees family. The first thing to say is - certainly from my researches - there are a large number of Rees's in Llangyfelach. This is not helpful and creates - as I'm sure you have experienced - a deal of confusion.
Unfortunately, I do not recognise the names of the relatives you have discovered - but of course they may be related way way back. I have not really got back any further than 1700 or so with confidence. One of my relatives - Morgan Rees (1720 - 1808) - was the founding member of the Salem chapel in 1777 and later the family had connections with Baran chapel. Morgan was the brother of my 5th great grandfather Thomas Rees (1722 - 1809).
I have an ancestry membership - but I keep the tree private. However, as a fellow member of the "clan" I will send you an invitation to view my tree as a "guest" - can you send me your email address?
Let me know if there is anything in my tree that helps in your research
All the best