I respond to most Irish posts. I'm not looking for anyone in particular right now.
For William Beatty B 1823 +/- 4 yrs, Co. Cavan, with the father's forename unknown, I found 1 rcd in 1819, Kilmore CI parish.
For William Beatty M 1850 +/- 1 yr, Co. Cavan, I found 1 rcd, 1851, Cavan CI parish.
For Marg(aret) Johnson M ditto, I found 0 rcds. This casts suspicion on the rcd for William's marriage. This wouldn't be the first time that I have found a rcd for one party to a marriage, but not the other. The only way to resolve the ambiguity is to view William's detailed M rcd. Will leave it to you to decide whether you want to risk 5 Euros for a peek.
For George Beatty B 1851 +/- 2 yrs, somewhere in Ireland, with the father's forename unknown, I found 6 rcds: 1849 Dublin, 1851 Donegal, 3-1853 Cavan, and 1853 Longford. Father's respective forenames were Thomas, George, John, George, Edward, and Alexander. Sorry - no Williams.
For George Beatty M 1876 +/- 4 yrs, somewhere in Ireland, I found 8 rcds: 1872 Tyrone, 1873 Antrim, 1873 Down, 2-1878 Tyrone, 1878 Antrim, 1879 Fermanagh, and 1880 Down.
For Jane Montgomery M ditto, I found 13 rcds: 1872 Armagh, 2-1873 Antrim*, 2-1873 Down*, 2-1874 Antrim, 1875 Antrim, 1875 Derry, 1875 Fermanagh, 1878 Derry, 1879 Armagh, and 1880 Fermanagh. The two POTENTIAL matches are indicated by asterisks. Suggest you compare these at the parish level to see if there are matching rcds for the same year, same county, and same parish. If so, these are likely for these ancestors. Protestant rcds are notoriously difficult to research. The correct M rcds, if any, SHOULD show their parents' names as well as other info.
For Jane Montgomery B 1855 +/- 4 yrs, somewhere in Ireland, with the father's forename unknown (or found above), I found 4 rcds: 2-1851 Antrim, 1858 Down, and 1858 Antrim. Father's respective forenames were James, George, Isaac, and Robert.
Hope this helps. Let me know of your results.