Tradition was to marry in the bride’s church so probably the MacCartney family were Methodists at that date. That chapel has baptism records from 1819 and marriages from 1836. Prior to those dates the congregation would have used the Churhc of Ireland for their baptisms and marriages. Unfortunately Grange of Muckamore COI has no records before 1845 so you probably won’t make any progress with them. Possibly worth checking Antrim COI as they go back to the 1600s. Copy held in PRONI.
Thomas’s farm in Oldstone is in Griffiths Valuation (1862). He had plot 3 which was a farm and 10 acres. (On the modern Oldstone Hill road.)