You could also just use a CC-licenced recording of the Kreutzer Sonata. For example there are two of them on this page. Unmodified audio clips don't count as making an adaptation, so long as they aren't being synced to a moving image, but you probably would want to use the Share-Alike recording instead of the Non-Commercial one if you're going to be using the clips for a commercial purpose.
Thanks. This may be a more productive approach and sounds like it could save me a lot of work. But let me ask the question from the other way around, i.e., not the technique to use but my purpose in needing these recordings. I am producing in early March a play I have written (see my other thread on this board for details), and will need several small sound files: a couple of Chopin etudes, a bit from LvB op. 109, and a few passages from the Kreutzer. I am finding Finale to work fine for the solo music, and the piano sound is acceptable. The actors are not expected to actually play their instruments, but should be able to simulate playing them.
The Kreutzer is more difficult than the solo piano, both for getting an adequate violin sound with pizzicato and for notating the more intricate passagework from the slow movement. Triplets, grace notes, and trills in Finale especially are a bear. (I could of course augment all the rhythms, using 8ths for B's 16ths, 16ths for his 32rds, etc.) I'm not playing the sonata complete, just 4-5 passages of 30-60 seconds each. I will save the passages as WAVs and play them through the theater's sound system as needed.
The theater will be selling tickets at $20 each, so perhaps this qualifies as commercial. But now that you know my purpose, can I use any of your proposed ideas?