Not workable. There's too many utilities missing here, which is ironic since many of these expensive modules need those unsexy, cheap ones to do what they do.
Tear this down, and start over in a larger cab. MUCH larger. Build what you think SHOULD work...then start paring that down while continuing to make sure you've got the basic functionalities you need.
One other point: this actually DOES NOT have enough VCAs. The three present are fine for CV/mod work, given that they're linear, plus you can use the module for mixing these. However, this also needs VCAs for the audio path to control levels and impose envelopes. A proper performance mixer can fix this, plus potentially add CV over panning, FX, and so on. Also, if you feel like you need to compress the audio, do this externally. You don't have the requisite space in this build to sacrifice other functions for something that'll be done easier via an external processor on the synth's output.
I should note that it's far more difficult to create a successful small build than a larger one. You have to understand what you want the instrument to do in terms of your own music...preferably before building!...and know how to fit those functions into a small cab with suitably-sized modules. But there's also the point that it's actually pretty EASY to use a small cab to create something that simply won't work...or, at least, it's easy without a proper knowledge of what you're trying to accomplish.
Also, get a copy of VCV Rack. Spend some time (as in quite a bit) in there and make the information somewhat innate so that, when you transfer the ideas from VCV to hardware, you already will have a build that works and, also, which you might be able to fit into 2 x 84 hp. VCV Rack makes it MUCH easier to see what extra widgets are needed in a given build as well as offering different ideas on what you might want to do. https://vcvrack.com/