Channel strategy for Newb with large setup.

[Lizard of Oz]

but also I genuinely can't fathom how I would plan out my routing on paper because I don't really know what ... what ... uh ... what I'm doing, haha.

I can offer some suggestions on how to set it all up, but to be specific we'd need to find out which device needs to talking to which other device, and why. So you'd need to tell me what MIDI gear want to connect to the MRCCs, and what you want to achieve. Do you want a dawless setup, or do you need different setups for different occasions, e.g. a dawless setup for jamming, another setup for sound design, and a production setup where your control everything with a computer or tablet, but still want your Octatrack to run in sync. 

In case you want to brush up on your knowledge about MIDI, see the SoS guide about MIDI basics (https://www.soundonsound.com/techniques/...ics-part-1), its from 1995, but still relevant, the MIDI standard hasn't changed since then.