Yes, that looks like the correct order for the two Thomases. In my search for an alternative Thomas, (the search that crossed my wires), I noticed on the indenture that mentions Lucy in 1754 that Thomas, the son of Morgan Richards, moves into Hendre Rees (sic) (Rhys), in Llanilar.
This would mean that Thomas, the brother of Morgan was the one living at Bryn Issaf with his wife Jane. (A clear separation of the two at last.)
II.229
1754, Sept. 10
INDENTURE, being a grant from David Richards of p. Llanddewy Brevy, co. Card., gent., to Thomas Davies of p. Llanbadarnfawr, co. Rad., clerk, of a tmt called Hendre Rees, p. Llanilar, co. Card., on trust for the said David Richards for his life, with remainder to Thomas Richards of p. Lledrod, co. Card., (second son of Morgan Richards of p. Llanddewy Ystradeny, co. Rad., clerk, dec., who was the eldest son of the said David Richards) and his issue, with similar remainders in succession to Rachel Richards and Lucy Richards, the dau’s of the said Morgan Richards, dec.