All of that sounds right...save for the buffered mults. While it's true that you need those to prevent voltage sag on the pitch CV, I seem to recall that the Klavis oscillators have buffering on the inputs, leaving only the Plaits...which I also think uses buffered CV ins. They're getting more common...thankfully. But as far as mults go, just get some stackcables or inline mults, and that'll be all you need. Again, keeping space open for function is key in a build of this size.
I actually had a certain "synthesizer" in mind when building this, namely: https://www.vintagesynth.com/eml/eml400.php The EML 400/401 was a revelation when I started using the one we had at MTSU in the early 1980s. I'd used sequencers before...the ARP 1604, Oberheim's DS-2 (I think that's it?), and Sequential's 700 were ones I had prior experience with, but the EML really went way beyond those. For one thing, it has the synth built-in (the "400" part), but the 32-step sequencer was just mindboggling. And three CV parameters...plus some gating as well. But the quantizer was totally bonkers...you could go from just a few steps per octave to SIXTY divisions per octave, and with some judicious tweaking of that, you could get the 400/401 to respond properly to 1V/8va CV...pretty cool, given that EML used a totally unique (and effin' annoying) CV at what's basically 1/10th volts per step, meaning that an EML octave was 1.2V/8va.
But yeah...I got this wild hair during the rework to...well, Avesta's into all these sequencer modules, and I can jam a 6U Arturia full of 'em...hmmmm...so why not make it have the general form-factor of the 400/401? After all, that device's form factor was just about perfect for a sequencer/synth combo. Plus, this gives a very clear upgrade path...add two more 6U cabs over time, make the lower left all about clocking, logic, comparators, and various stochastic bits (all super-important in doing truly complex generative work), and the lower right can be all modulation by turning the upper right into all voice. Pretty cool when it works like that! Plus, since you'd have an initial Tex-Mix setup in there, all you'd need to add more inputs to the mixer would be another faderbank of four channels...either mono or stereo. Although, with the master section being all but MADE for that DualFX setup, expanding the Tex-Mix would be far less costly and irritating than having to get Yet Another Device.