William Fargher is going to be a problem - the Lonan registers are deficient in the late 18C and you need look at Bishop's transcripts which are not complete for the gaps in the register.
Wm in 1851 claims birth in Lonan and age 64 - this suggests a birth around 1785-1788 which is one of the lost periods in the register - I have two Wm's baptised in this period from Bishop's transcripts - one potential father is Philip (supported by Wm's son's name) - no mother's name is given but my guess is that Philip married Margt Mylchreest in 1791 in Lonan and these are the parents.
However the Lonan burial register is also very unhelpful at this period - Wm is noted as "in mountain" which suggests a small holding in the hills probably an intack if you want to chase this aspect (see Lib Assed + Lib Vast under property on my MNB CD