Is there a way to isolate individual instruments and vocals in a single track recording?
Probably not.
If the instruments are triangle and double bass, then you can partially get rid of one or the other by filtering out the low or high frequencies, but generally the frequencies of each instrument will overlap, so you can’t remove one without affecting the others.
If you’re feeling experimental, you could try ISSE:
Haven’t tried to separate instruments myself, but the demo looks interesting.