It is a really good piece! The harmonic approach of the piece is really good, and its use of dissonance, as well as contrast, is effective. It is clear that you understand and utilised the conversational textures well. What I think you can probably explore is more distant modulations and extended chords, perhaps in a more contemporary style. You could try a more motivic approach to the piece, and explore the usage of extended string techniques, which will come naturally over time as your experience with strings gets better. Amazing that your double stop writing for strings is well-done and not overly-straining. I think however, that you could experiment with the return of the fugue in a different key from the first iteration to add that element of surprise.
In the live recording of the piece, I think what would have been great would be if you could advise them to use more baroque style of playing especially given the nature of the piece to really enhance the effect. Baroque bows in particular, and require a faster velocity of the bow to play. There is a strong tendency to use the extreme ends of the bow and play those parts of the bow louder compared to the middle, as well as a characteristic tenuto-like articulation to the key notes of the piece. That could be something that can greatly enhance the texture of the piece, given its nature of a Baroque fugue.