This may not fit, unless you do some editing and are prepared to do it as an abidged solo piece.I'll just name it because it seems like it's not very well-known, but Chopin's Variations on (Mozart's) La ci darem lo mano (I think that's spelled correctly).Probably not, but I just like the piece and from a cursory reading through some of it, it seems as though a good many "Chopinisms" are there in nascent form. Plus, it's a good aria, people would probably recognize it, if not Chopin's variations.
The piece that inspired the Schumann quote: "Hats off, gentlemen! A genius!"Beautiful piece, and technically very challenging. Not to sure if it would fit in a program with all four Ballades.
The Ballades are major works, both technically and musically challenging. I would be inclined to include miniatures to balance the program. After all, salon music and intimate performances were more to Chopin's taste than grandiose recitals - the miniature is an integral part of Chopin's music. There are many selections that are not frequently heard, and I would urge you to explore them. One possibility is to pair a Ballade with a set of miniatures composed from the same period. Maybe include some commentary as to life events that Chopin experienced at this time.You could also do a program that explores music by other composers that was influenced by Chopin, and the Ballades. Or maybe a program with Chopin and his contemporaries, music that was being written at the same time as the Ballades.