Oh, right. Actually, we did consider Goidils; they were comparatively united and well-off in this period, but aside from shore raids and conquering Mann, they did little until the Roman conquest of Britain (which was followed by the setting up of huge numbers of Irish slave colonies along the British coast, a large raiding invasion at the request of the recently formed Picts, as well as large migrations; the latter kingdoms of Cumbria and Regydd both had substantial Gaelic populations because of this), and the conquest doesn't occur within our period, so it seems needless to use them; by that point, they'd become steadily more disunited anyway, which, due to territorial claims and the like, eventually led to the Ulaidi invading what would become Dal Riada.