Yes, but why the call-and-response or lining-out of Gaelic Scotland, as opposed to the call-and-response of non-Gaelic Scotland, or England, or France, or Africa(and which parts of Africa). If this is worth looking at, it's worth looking out prperly. TheIsle of Lewis may be the only place doing it now, but who was doing it then? That's the question to ask.
Incidentally, call-and-response and lining-out are two quite different things. There is very little lining-out in gospel music...it is hardly the core of it, is it?