Prongated, yes that's another idea with the major/minor shift. Don't know how it works until I've tried though. Do you play it like that?
C7-9 in bar 7 is probably the one. Again, your idea about more drama is of course based on another interpretation. I don't think I could emphasise it more according to how I play the previous bars, or should I?
I've used various editions, pre ww1 peters and two post ww2 henle. You are quite right about me not paying scrupulous attention to notational details!

I play legato where it's indicated staccato and vice versa. I should probably spend some time now looking at the score again.
Teresa, of my three editions, one is completely with ornaments in the repeated section, one is without, and one is with both. I choose not to do these ornaments partly out of doubt about their authenticity, partly because I felt some sense of purity without them, and partly because of laziness in learning them.

Counterpoint, I don't agree except about sentimental. Actually, reading about him makes me think that he was quite sentimental as a person, but that's another thing. I can't see his music as being cheeky, I don't think he liked to joke in his compositions, or that he was ironic, and I even think his music often talks about sadness, especially in very quick changes between light and dark and more so the older he got. But perhaps that's just me being sentimental.

Thanks all three for you comments!