(At the time being some DAWs can't route audio to plug-in instruments but only to plug-in effects. That's why many still need the effect plug-ins.)I don't know if logic can do this, and if so - how to.
But if you in Logic can route audio into both plug-in effects and plug-in instruments, then you just have to
remember you need to play the instrument to get any sound.In principle you need:
1. a audiotrack/ audio signal that's is routed into
2. a track with a MIDI instrument (like Mini V3, Modular V3 and Arp 2600 V3).
The instrument has to be set up to accept the audio input, and that you can read about in the instrument manuals.
3. Then you also need to play the MIDI instrument while sending audio to it. Or use recorded notes that play the instrument.
I think there is videos on the web about how to set up a vocoder in logic. I suggest you watch them as the principles is the same.
Perhaps this Video can help you:
https://www.youtube.com/watch?v=V2o5uyp1iZEIt look like Logic can send audio into plug-in instruments. But i can't test it as i'm not a Logic user.