Jean, I have information about Skillicorns from Ballaragh, but my information doesn't correspond to what you have written. I have the John who was the son of John & Kathrine Skillicorn as bapt 25 Nov.1744, Ballaragh.
The parish registers have many children's bapts with, for example "of the Mountains', "B.Arragh", "Skinscoe", "the Fells", etc., which is crucial when usually only fathers' names are given. They could have had an earlier son John who wasn't recorded under the place name, and who died young, but that can only be guesswork.

You say that John and Katherine "were supposedly parents to John b.1725, Henry b. 1733 and Jane b. 1723". Supposedly from where?

There is no way around the need to look at the original parish registers when researching Lonan families.

Sue