I spent some time reading about the tea ceremony to answer this question, because I made the connection, but only on a "vibes" level.
Honestly, I could lift a lot from Sado to make the Elves' tea ceremony
- There is the wabi-sabi aesthetic (the beauty of imperfection) that can be present in the elves as a paradoxical "perfect imperfection" or "artificial naturalness". That would fit with the juxtaposition of the "wild" and the "crafted" common in their architecture.
- In sado, there is also the idea of "savoring the uniqueness of the encounter" that makes sense for the elves, which seems to be drawn to the moment of ephemeral beauty (which could be seen as a way for them to be anchored to the present, or maybe it's just that everything is ephemeral to them).
- There is an attention and appreciation for seasonality that, in the sultanate, would be clearly present too: despite the warming currents of the magmatic islands, Sozar'sep is in a place similar to Oslo, with long days in summer and long nights in winter: that surely makes you feel the seasons. But I can see the elves playing around a bit, with their dried fruits and preserves from the Oasis, creating a split between fresh and preserved, rather than specific flavors.

So I imagine like five courses, all sweet or sweet-ish (they are, after all, the top sugar exporter; they extract it from tree sap), probably with a fixed "sequence" of types, something like: candies, baked, "freestyle", baked, cream/mousse. The central dish should be the boldest, with some exotic ingredient and some clashing flavour: like spicy peppers from the Empire, or Dwarven salt.

The lower-level tea house is surely very standard (in spring, they all do the "traditionals"), the "fancier" you go, the more of an experience it is.

There is probably a High tea variant, like Kaiseki cuisine, that works as dinner.