The mixing stage involves a lot of minor (and major) tweaking. Here are some things that you might want to do, which aren't adjusting the fader and panner settings:
Re-align tracks to ensure that they're synchronized.
Find a meaningful way to incorporate the region with the sound of the chairs.
Compare the currently-unused clarinet regions with the in-use ones. Try different combinations of the regions, and remove the unused regions from the session.
Compare the currently-unused strings regions with the in-use ones. These regions are much longer than the clarinet regions, so you might even want to pick and choose ranges of regions to switch back and forth.
Have a friend--or at least somebody else--listen to the mix you're preparing. Get their opinion on difficulties that you may be having, or use them as a more generic listener.
Listen to the mix on different kinds of reproduction equipment (speakers and amplifiers). The same audio signals will sound different when played on different equipment.
