Okay that becomes really an Ableton question rather than a M4L question, as there is nothing that really distinguishes an M4L device from an Ableton factory device, since you will not be editing your M4L devices.
For audio routing, see Ableton’s Internal Routings. You can duplicate audio from any audio generating device and use it as an input to a new audio track. If you want to then mix it with other signals, you might either set up some grouped audio tracks as a bus or you might also set up a return track bus.
If it is MIDI note data, you can do something similar with MIDI tracks (should be described somewhere in Ch 14 as well). If it is MIDI CC or automation that you are looking to move around, you will want to use macros most likely, and maybe some sort of Multi-Mapping device if you want the data passed across tracks.