Back to the patronymic for Donald Mackay who married Catherine Mackay on 15 Jul 1777, my copy reads "Macneilicenicolicuilam" (no d in it). Separating for the macs and the ics, I get "mac Neil 'ic En 'ic Ol 'ic Uilam" The "Ol" is a bit unusual but, assuming "Dol" is meant, I read the patronymic as " son of Neil, the son of John, the son of Donald, the son of William. BTW, "ic" in a patronymic usually means " 'ic" which is a common contraction of mhic, [pronounced "vic"] the genitive case for mac. For example, A, son of B, son of C would be: A mac B 'ic C. When spoken, and when written in the minister's phonetic-Gaelic record, they appear to be one word.
There are at least two baptisms of children of a Donald Mackay with very similar patronymics: 4 May 1778; "Donald Mackay, alias Macneil macen mhic Dholicein, tenent in Hope, John" [the words are separated in the record] I take this as: son of Neil, son of John, son of Donald, son of John. [rather than William, as above] Also, 5 May 1781 alias virtually the same but now in Mercan, twins Katherine and Bessie. I don't think it is surprising that the recorded patronymic for the same people vary occasionally. I usually check the patronymic from the marriage to the subsequent baptisms.
Enough for now!
IanB