All that I remember is that in Edward Richard's will he left quite a lot of property to the school at Ystradmeurig. In addition to that bequest there were other bequests pre-dating his death that may have made provision for the Church to use other properties, (Bryn Issaf may have been one of them). The Rev. Owen Owen was recorded as living there in 1798 and he may have been a retired Clerk or the actual Vicar of the combined parishes of the area. (Rev. John was the Vicar of the parish of Llanerchymedd but also the Vicar of 5 other parishes).
Here is just one of those bequests.
1757. Edward Richards, Schoolmaster. Accordingly in 1757 he gave to the Bishop of St Davids, Viscount Lisburne, William Powell, clerk, of Nanteos, James Lloyd of Mabws, and Thomas Hughes of Hendrefelin, in trust, 'the messuage, tenement and lands, with the appurtenances, commonly called Bryn-pervedd, situate in the lordship of Sputty,' and other properties to pay a schoolmaster, etc....
I agree with you in thinking that the church, and the school at Ystradmeurig, through Edward Richard, had a finger in John becoming a cleric. Living in a place like Bryn Issa he must have had a helping hand to manage an Oxford education. (He isn't referred to as 'pauper' or 'plebian' in Alumni Oxfordiensis).
Regards, Peter