[@Antarctic Termite] Clothes on urtelem could be interesting, and is somewhat feasible. Only tricky bit is when they roll up to roll around, or burrow through the ground, although blankets make sense. With their interactions with other civilisations, urtelem probably have access to textiles, and have probably tried wearing those sheets of textiles.

Structures on their backs would not be permanent. Urtelem seem like sturdy foundations, but they'd be pretty earthquake prone. Structures will be fine when upright, but will collapse if they roll over or anything like that. However, stability issues notwithstanding, this actually fits in well with the migratory nature of the urtelem. Should they ever have need for buildings, urtelem can carry the buildings around with them while migrating.

These will need to be explored IC.

[@Muttonhawk] While I'm no biologist, panting should be adequate for providing a hain's cooling needs. It works as a primary cooling mechanism for most animals (humans are a notable exception, who use sweating as a primary cooling mechanism). This has the drawback that hain would not be able to run long distances without stopping to pant every so often, but this is a minor drawback.

What I haven't wrapped my head around is how a hain's internal organs are supported for a creature that size without an endoskeleton, or how their muscular system is wired. There's probably a plausible explanation; I just don't know it.

[@WrongEndoftheRainbow] Dwarves follow a basically human physiology with greatly enhanced ability to metabolise ethanol (which is a brilliant source of energy if you can metabolise it fast enough). I see no issue.