It looks like Brian got that first question spot on so I will not dig into that one any further.
I know Suncroft well, I have spent many an evening in the Croft inn, in the middle of the town. The name O'Neil is still quite common around that area. Talking of which You find generally names will start out in a specific area but will spread across the island quite quickly. For instance, the O'Neills start out in Tara around 360 AD but by the 10th Century, they are a Prominent name in Ulster, Limerick, Waterford and Carlow. Today there are O'Neills all over the island.
So you also asked what would help get more info. Yes, names, dates and areas are the easiest way to start tracking things down. If you have any specifics please post them and I will see if I can dig anything up for you.
I look forward to reading your reply.