The Irish Celts were there during the post-Roman period, mostly anchorites it seems, as the Norse referred to them as Papar. This suggests they didn't have any self-replicating settlements, but I suspect that various monasteries in Ireland were sending people there consistently for quite a long time. The evidence from Shetland and the Hebrides is that the relations between Gaelic anchorites and Vikings were quite good. Given they had no gold or women and little food they seem to have left them alone, or perhaps they were doing something useful for them, hard to know what.
Anyway, if the Irish had tried to put actual colonies there, the Norse would have killed the men and stolen the women as they did on the other North Atlantic islands.