I like it all. Only thing is the castles on the Uppland side of the passes need non-wilderling names, though the wilderlings would obviously have their own nicknames for them. So we need to Saxonize, Celticize or Latinize Iron Hill Watch and Forest Tower. I'm saying we call the passes in the Uppland-Norwald border the Reaver's Roads (though there's no actual roads).
Speaking of which, the Crownway should stop at the north edge of the Darkwood, as until recently that was the edge of the world as far as Neumark was concerned. A modest castle (Forest Tower) there makes sense.
I say House Alton's seat is Ristalinna (English speakers don't tend to use the double-i). Pesalinna is good for the wilderling town on the river.
Regarding the Lord of the Shire, my first reaction is "too hobbity."

In any case wouldn't Shire be a commonplace unit of territory? I rather like "Lord of Hearth and Harvest."
I'm also thinking we need to move the king's younger late son out of the Dawnlands. Otherwise Summervale starts with too strong a position, with a vassal to their north and an infant nephew (and likely pretender) to their south. The as-yet-undefined blue-green land east of the Crownlands looks good for him, as a vassal of Dawnlands.
For balance reasons, I think each Great Lord needs one major vassal, along with the holdings in their own territory. I'm thinking the Great Lords (the ones to be filled by players first) should be Norwald, Uppland, Fenland, Midland, Summervale and Dawnland. Possibly one more, a nautical power on those western islands with a vassal in the penninsula due west of Fenland. Fenland needs a major vassal, so I think maybe the river valley and east side of the lake, inland to a bit past the road.
That still leaves us with a fair amount of blank land. I'm thinking we can leave part of it empty as The Barrens, a rough analog to Ireland's Burren or the Scottish Highlands: a hard land filled with many small, highly contentious clans with chiefs that are theoretically subject to the crown. A potential source of raiders against or allies for players, but not playable themselves.