Particularly good points.
For cultures that may inhabit a small area[1] it's probably simple.
1) What materials are there? For the dwarf, there's al(most al)ways rock, you'd think, and elves are probably going to ensure there are trees (and do their elfine thing about it), but humans on an open plain might need to be sparing with everything but turf, for at least newly established settlements.
2) What do conditions dictate? As said above. Though with licence. Winterfell's 'spindle-tops' of wood are(/were?) quoted as impractical with possible/probable/periodically-certain snow in that region, not being fairy-tale/disneyesque/germanic that would not crush, but I think there's canon-excuse that if the wooden roof (installed as a machicolated hoarding, astride the stronger snow-proof roofing, for practical defensive purposes) gets damaged, it'll get fixed. (As soon as it seems needed. (Bran may have 'fallen' from one of the towers that hadn't been 'reopened' since a prior reconsolidation of active living/utility/defensive areas.>
3) Some cultural quirk. As above, a dwarf may always dig, an elf may prefer to nest, but other than that there's the geometricism (round/long/square-houses), a tendency towards a material that isn't ultralocal (but regional, at least, without needing cross-cultural importation) that might be used in 2nd+ phase of building (replacing/surrounding whatever establishing buildings had to be rude-cut into the landscaps first, in all but the most planned-in-advance towns with materials carted in especially for the founding - a sign of a rich, (over?)confident and expanding culture), little details like many small windows (not that this is much noted at the moment) vs fewer larger ones.
4) Building use standards, specific to the building-type and culture. Do all religious buildings 'face' the same direction/towards one worldpoint, or best effort? Is the town-hall (or equivalent) an easily accessible 'public' area, access and egress through any of the gaps between the roof-supporting columns to come and cheer your opinions out as one of the people, or is a defensible keep in which the local business is conducted in closed-sessions, or strictly vetted access to the public gallery to discourage troublemakers? Once homes are big enough to have more than one or two rooms to them, is there a 'reception' room/'front room kept for best'/granny-annex/separate bedroom-cum-office for husband and wife/etc.. or do any or all of these become(/stay) subsumed within the original 'family' room?
5) Historic devopment. Not just when invasian happens, but an intra-cultural shift. Bits of York, for example: Modern çsympathetic' buildings, a few brutalist designs, interbellum architecture, Victorian streets, mediæval streetplan, distinct viking naming/influence, traces of Rome preserved/recreated (with plenty of in-betweeny bits), where there are three or four main 'invasion' changes, but many more is just signs-of-the-times, like the huge portal cut through the city walls for the newly-developed railway that doesn't even go in there any more, with the 'new' through-station off slightly outside.
I'm not entirely sure how Tarn would do half of all this (never mind a few more ideas I couldn't quite classify) in a worldgen procedurally-led process capable of generating a century or two (or ten) of 'history', and perhaps a bit of faked pre-history too, of a non-stagnant site. Maybe a few less-ambitious twists, to start. Assemble a dozen 'template temples', and use one or other of them for every founded settlement, when it becomes time to render, plus consistent-with-home-civ also add new/additional ones to places later touched by that other influence. A 'ruination' process, or ruined-version by straight template can be used where a later change is judged harsh enough. (Plus "ruined cities" is an Adventuring trope, whether you expect a little idol under a boulder-trap in a jungle or a city with hidden artefacts buried by dunes in a desert. We probably should see some, however so created. Plagued towns left abandoned by drastic depopulation some time ago; refugees fled a whole front-line village quite recently; trading post anticipated copious future residents but fell on hard times, after setting up plots, and those who had come then left...)
I'd like to see some 'Old Town, New Town' bits (c.f. Edinburgh), if not 'Old New-Town' (Milton Keynes? <Foo> Garden City? Noo Yoik?) from afresh, but could be fiddly to work out the parameters involved in implementing them (especially such that every city is not just Edinburgh, more or less).
[1] This may be circular. A sub-culture of a bigger and more expansive example might find they have developed a localised style distinct from their parentage and thus become known as a new culture: "You moved here from Caveshire? I suppose you found you had to build your own cave, here in Swamptopia..."