I searched the Irish Family History Foundation's database. It contains 12,000,000 surviving rcds for abt 65% of Irish counties. Rcds are increasingly sparse B4 1840, rare B4 1800.
Note 1 - Without a KNOWN parish, the chance of an ancestor's rcds NOT being in this database is AT LEAST 35%.
Note 2 - Only 1/2 of Co. Cork's rcds are in this database.
Note 3 - The RC church kept control over most parish rcds from Tipperary (north). These are ONLY available thru the Tipperary Family History Research center at a substantial fee (regardless of outcome).
There are two M rcds for the surname Kemp in Cavan in the 1820s: 1826 Margaret, and 1827 Araminta. Neither is in Co. Killinagh parish.
For ???? Rorke M in Cavan in the 1820s, there is only 1 rcd which corresponds to one of the two rcds for Margaret: Patrick. Will leave it to you to screen at the parish level to see if there is an exact match. If so, it is likely for your ancestors.
Google the Foundation's name to lead you to this database. Register, opt to be notified as rcds are added and browse. Pls post your search results to my genforum msg.