This is some time ago and you may have stopped your search plus I had messaged you on ancestry with regard to Irwin. The oldest son, Alex, was my great grandfather. It is said that the family came from the town land of Aghagallon just outside Omagh before moving to Altmore. They were Presbyterians. I met Col Irwin on his visits to Altmore in the late 70’s, I was a child. Most of this info is in my ancestry message to yourself.