Re-reading Shadows of Europe, I was looking at the list of Danaan families, when I saw three that simply didn't belong.

Burke of Ulster*, Butler, and Fitzgerald are not the names of Gaelic Clans, but Anglo-Norman Armingerous Houses, granted nobility by Edward III of England and his successors. As it was (probably) the IEs trying to gain nationalistic credibility for the Seelie Court and the Ways and Paths of the Wheel that caused the Blight of the Tudor Estates, what are those families doing sending their scions to the House of Stewarts? They don't necessarily need to sprout thorns, but their place among the Danaan families should count against the credibility of the Tir's government.

*as opposed to Burke of Connaught and Munster, who are descended from "kings of the hill" in southwestern lake country.

In-game, the reason could be intermarriage. Some of the Anglo-Normal families intermarried with the Irish nobility. I can't speak to the specific cases, but I assume that would be the in-game reason. Or perhaps the families were just too well-placed and the Tir government bought their cooperation with some measure of power and they are very controversial. Heck, they could be heavily involved in the Unseelie Court.

When they set up the new government in TNN, did they invite those with money and/or local political clout into the upper levels to give it some sense of legitmacy? If so, and if those names had the cash and power behind them, that might explain it.

I can see some local saying, "the big guy is backing the elves, so it's a good idea!" all the while hoping for some patronage.

Then I guess you'd have to assume the temporal power angle - those families just had too many connections to not subvert into the power structure. Why not - things like that happen all the time. Keep you friends close and your enemies closer and all that.