The Preamble is explicitly based on a work by Schubert, which formed the spark for the whole work. It was a se5t of variations on his 2nd Waltz from the D365 set. I believe the variations have been lost (though recently "reconstructed"). The original Waltz might make a nice opening:
Carnival, which the Schumann depicts, is the day before the start of lent, so for an informed contrast perhaps follow it up with something with a Lenten theme (or at least something along those lines)?
Oh.... and what are you doing with the Sphinxes?