Each of the dances exhibits direct (chord-to-chord) mediant shifts. Each on its own is not extraordinary -- even as early as 1820 or 1821 -- but, taken together, they seem to me a remarkable hint at mediant play in Schubert's improvisational-/compositional- thinking at the time.
In n1 (D145n1), a fanfare-processional first phrase is immediately answered by a shift to the relative minor (R). From first strain to second, also, a P transformation, a hint of a linkage between different modes of efficient voice-leading on the "Riemannian hand."
In n2, the R move is complicated a bit more by the octaves but is again associated with a significant design articulation. Ditto the LP move between strains, and P for the second strain's latter half, which transposes the first strain's second half from C to A (an RP move if it were done directly).
In n3 (which is D365n29), the design/transformation alignment continues between the strains (chord roots D-F#; move is LP).