We already have some information about the Davies family of Penbryn from various indentures. I here add some snippets from them.
The 'Fine', original is dated 1762
[Thomas Richards, gent. and Jane his wife, of two tmt's called Penbryn-issa alias Tythyn-y-bryn-merllyd, and Bryn-merllyd alias Tythyn-bryn-issa, and of a parcel of land called Gorse-glan-teify (60 a.), p. Lledrod, co. Card., to the use (as to the said parcel of land) of the said Morgan Harry in fee, but that no uses had been declared as to the said two tmt's, they therefore declared that the said fine should enure (as to the said two tmt's) to the use of William Davies of Penbryn, Lledrod.]
[Indenture, being a mortgage for £300 from Thomas Richards of p. Lledrod, co. Card., gent., to Elizabeth Davies of p. Sputty Ystrad Meirick, co. Card., widow, of two tmt's called Penybryn-meillid and Bryn-llyd in said p. Lledrod. Dated 1764.]
[ an indenture was made on the condition that the said Richard Davis would release the said tmt's to his brother before 7 April 1773, and that the said Richard Davis had not paid the £650 consideration money, and was not to pay it but to hold the said tmt's on trust for the said William Davis.]
Extract from an indenture of 1778
[ Elizabeth Davies of p. Lledrod, co. Card., widow, and Richard Davies of p. Llanvihangel Lledrod, gent. (brother of William Davies of Penbrynn in same p., gent.)
Entry from FreeReg. Infant Elizabeth Davies, death in 1798. (another sibling?)
If you add to this the fact that Joseph's sister, Ameilia, married the John Jones, (son of the Smith at Swyddffynnon, which is only a stone's throw from Penbryn and Bryn Issaf), then this hypothesis has more going for it than any other, so far.
regards, Peter.