High-level Talents, especially Talents who were trained by masters with similar Talents, can definitely get blatantly supernatural effects after a decade or two of build up, though Talents that can produce lasting magic items or other independent magic are very, very rare, and almost all have to do with metalcraft, Illusion, Healing, or Shaping. Most Talent-based supernatural abilities are, like, self-focused or temporary, though I'm not sure exactly how to describe it. Aspect powers maybe are the right direction? My memory of Nobilis is fuzzy.

There are pretty large sections of the city that are shaded by the farms most of the time, and they are commensurately more focused on things like mushroom farming, storage, manufacturing, and other less light-demanding purposes rather than, say, housing or storefronts. As for how they produce enough food, it's a combination of Talented farmers, Shapers providing supernaturally fertile and aerated soil (spoiler, ROT13:) naq zntvpny trargvpnyyl-ratvarrerq fhcre-pebcf gung jrer perngrq ol gur jnecre rzcver gung cerprqrq gur funcref pbzvat vagb orvat.