ai..you should'nt be assuming anything about music when it comes to musicians. My parents, you could say: "Chopin wrote 3 posthumous etudes", and they would answer, "What is posthumous?". Unless I played it, they would'nt know that Chopin ever wrote etudes, nor what an etude actually was or whatever it meant. Commoners are all alike.
But musicians have heard Bartoks Orchestra Concerto, and know of the most obscure beethoven sonata, and know in what Piano Sonata you find the Marche Funebre by Chopin. It seems arrogant(or naive) if you assume that two thirds of the participating audience haven't heard of something as obvious as Chopin Etudes. Pherhaps an unfamous Bach Sonata for solo Flute or another Suite for chamber Orchestra by Telemann. I feel insulted.
As for the op.posth. Etudes, the one in Fm is unusually beautiful. But I would say the one in Db is a bit shallow and..the last is a bit boring. That's my opinion.