Hi
One thing to consider... Most of these "color organs" assume the input would be the full audio frequency range, so they include filters to separate it into different frequency bands (for example, low, mid, and high). The output of filter is then used to drive a different set of colored lights. However, if each band member's audio channel drives a dedicated lighting unit, then the circuit really doesn't need the filtering. You might be able to save some cost there.
eT