Wow...that is one seriously expensive ADSR. That's actually where I'd start: get rid of it. Instead (and keeping with the preponderance of Erica stuff here), replace it with Erica's Black Dual EG/LFO. It's cheaper, for starters (so you can sell the AJH cheaply and still afford this module), and doubles up on its functions. And you do want that...having separate envelopes for filter and amplitude is actually pretty useful, hence why Bob put both in the Minimoog.
Mixer? Sure, why not? It's kind of in the wrong position, though; instead, swap it and the quad VCA so that you can control the oscillator mix with the VCAs, then the Stereo Mixer can work with some sidechaining-type patchwork (you need stackable cables for this, fyi) to send the filter to both the mixer and the Pico DSP, then return the DSP back to a stereo pair on the mixer in sort of a cobbled-up AUX send/return fashion. Also, if/when this gets expanded, you'll want that mixer to add in the signal from whatever expansion skiff you put together, so it's a good plan for the future to have that.