[I]Two[/I] prospective new players? Oh my... I think I nearly fainted there for a moment. And they both want me to add new races into the universe, though I imagine that at least these "Éireannach" would be relatively easy to fit in due to their nature and location; for them to have a place in the west with their culture - apparently waging wars rather liberally against neighbouring civilized nations - they would have to be [I]really[/I] far west, past even the lands of the Xhurl-njok, which would act as a natural barrier for them to have much interaction with nations to the east anyway, due to the inhospitable nature of the Xhurl-njok.
Reading through your description, Legion, I do find myself wondering: how does this race differ from humans? You only really described how they were similar to humans, and to me it sounds mostly as though they [I]are[/I] humans, just with a different culture... which would not make them a new race, but rather a new nation. If I'm wrong, then how do the Éireannach differ from humans? That's really a big factor in deciding whether they are even acceptable or not.

Their culture do sound familiar, though... to me it sounds like a cross between the Qetemak nomad tribes and the Kátimit barbarian territory, with the main differences being that the Qetemak don't build settlements at all and the Kátimit are generally more settled than what you describe.