Really cool variations. I thought it was really clever to use given Ab-G dissonance as a E7b9 chord. I also liked the chromatic bassline in Var. 3 and how you harmonized over it. Lastly I thought it was pretty cool that you ended Var. 3 on an E7, which prepares for A minor key of Var. 4.
I was curious how you came up with the below resolution (Var. 2, m. 11). In my head I see it as a Abmin7b5 without the B, but I can't figure out how it resolves to the C5 chord. It works nicely, so I was wondering if you could explain how it works?
Also, I wondered if you might explain how you came up with the 16th note runs in the right hand in Var. 5, m. 33-37. It's super cool but I have no idea how you came up with it.
Thanks for sharing!