Many thanks for your input! I feel your enthusiasm for these types of posts. They are, after all, a kind of public challenge for which we can showcase our knowledge while also collaborating with others. I would personally like to get more involved with such things. It would be awesome if we maintained, as a group, a repository for knowledge in the art of composition - for example how to consider voice leading against chromaticism. No doubt we would need distinct zones for functional harmony and otherwise to accommodate people's diverse ascetic interests on this forum.
That aside, I had seen E as a common tone opportunity for a pedal, potentially, but that seemed a little boring and unadventurous. However, as you suggest, perhaps it is neither necessary to add further complexity if the outer voices are already doing something interesting and distinct. Nonetheless, I thought I would rise to the challenge.
I like your solution - that largely moves in thirds with the base and for which there are opportunities for further refinement by recycling some motifs from elsewhere in the piece. I am unsure about the treatment of the third bar as E7, considering the bass resolves to A minor, although the only note that may undermine this is the D in the clarinet during the third beat of that bar.
You're right about the b natural in the bassoon - that was an oversight on my part.
I will have a tinker over the coming days and report back here with what I've come up with.