I messed with it for a hot minute, then gave up. I think you might need to go back and research the way you want your MIDI signals dealt with, as there's an awful lot of MIDI-specific things going on here that seem superfluous (such as, if you have an ES-9, why ALSO have a separate CV-MIDI converter module?). Also, I don't get the excess external preamps...especially since I don't also see an envelope follower, something which you will 100% want for picking off dynamics as CVs. Basically, the "if this were..." argument seems moot to me, as this isn't how I would've started in the first place.
I strongly suggest going back to square one here. If you have these modules on hand already, especially the ES-9, go back and see how that one module alone supplants all of these unnecessary MIDI-based things. Given that I have something similar in my modular "sandbox" here (a MOTU 828 mkii + Ableton CV Tools) I can confidently tell you that you're piling a lot of unnecessary stuff into this build. And if you must use MIDI over the more precise and modular-friendly CV/gate/trig I/O of the ES-9, just use its MIDI expander, which is already in the build.