For John McAllister B 1844 +/- 2 yrs somewhere in Ireland with the father' forename unknown, I found 25 rcds. As expected, all with the exception of 3 were in northern Ireland.
For Rose McKinley B ditto, I found 1 rcd in 1842, Antrim.
The information shown on the IFHF rcds varies. It can only transcribe what was found on the original parish registers, etc - this includes spelling errors, abbreviations et al. The data content depended greatly on what the priest or clerk felt like entering on the day he/she created the rcd. In a few cases, the smallest level of detail is the townland or village. In most cases, the smallest level of detail is the PARISH.
Generally, if you can associate two individuals with a specific parish within the same county at the same date, this is close enough.