Perhaps you could use a SelectableAudioOutput on each Oscillator in the Replicator, and set its Channel to
?VoiceNumber
Then each of your modulators would be accessable on a different channel.
What are you modulating with your QuadratureOscillator? If each of the four is used in the same way, you could put the Sound you are modulating into the Replicator as well. In other words, modulator-->carrier-->replicator.