Even better if you can voltage control the frequency. Then if you can introduce a delay in the oscillator output, filter it, then feed back into the variable resistor(?) that controls its frequency, you have the basis of a mini-FM synth - if you can get it to stay stable in the normal human hearing range of course...
Nothing really to add on the engineering side, just seeing how it looks, I want to hear it making some noise, although it's not its intended purpose.
Nice work on figuring out how to get it going again!