Why not?
I don't know in Qtractor, but in Ardour you can do that... For the audio signals, even routing to their inputs mono outputs of other tracks (and/or system inputs), or by sends.
And for the controls you have automations.
I don't understand the problem...
Best regards,
Natanael.
Ardour does not see three inputs of, say, a LADSPA Vocoder. It sees only two. LADSPA Vocoder has three and you need three to create an effect.
L.V.