How does this look? Am I missing anything crucial? Too many sound sources perhaps? Not enough utilities? Not sure. Thanks!

It's close...but if it were me, I'd drop one of those Optomixes, because there's plenty LPG processing for audio in just two with this few audio sources. Instead, you really need an output module as well as some sort of final mixer to bring the drums in with the other signals. A mono mixer would work fine, but you're going to want a 2-channel output module so you can take advantage of the Pico DSP's ability to 'stereoize' your mixer signal. Otherwise, the compliment looks right; you can 'steal' the extra VCA on the Lifeforms if needed for CV work, because the Optimixes will work fine for that patchable's final VCA instead. Maybe a couple of qualms about the lack of 'proper' envelope gens here aside of the one ADSR, but if you tinker the Maths just the right way, that ought to work out.

Put a modDemix instead and added the Doepfer mixer.

Swapped a drum and a mixer for the Sinc Iter. Needs some craziness.

Seems better at first, but losing the Optomix means you lose the audio VCAs. I agree with the Sinc Iter move, tho...

But, another idea: since you need some percussives, why not use a small, separate cab for just percussion modules and put those under the control of something like, say, a BeatStep Pro? By removing drums to that, you'll be able to open up the space for the output module as well as bring back the Optomix. And also, jamming something like 6-8 percussion voices into a 42 hp powered cab is relatively easy. Something like...

Not a bad idea. I am planning a 3rd row after I get the majority of these modules and use that for drums/sequencing. I really want the whole thing in one unit for portability.

...something like...THIS?
ModularGrid Rack
Just an example here...this is built into a $200 powered Zissou Pulplogic case, but I have to admit that I'm nervous about the power draw in this, as my spec came out to 324 mA on the +12 rail, and the cab's maxes are 350 mA on each rail. But the point is, it's possible to concoct a tiny little case strictly for drums and just sequence the whole thing off of a BeatStep Pro. Like that sequencer, there's eight drum modules here, although you'll likely want to not use one along with the others at any given time because the HATS909 module needs triggers for 'open' and 'closed' to get the sound right.

But yeah...stereo mixer + a 4-1 mono mixer for all your mono/center sources like kick, etc, drums, a mult to split a trigger to double a drum pair, and a stereo out. Very simplistic and small, but also pretty powerful. Stepping up to, say, 60 hp would probably yield more room, but I opted for the Zissou because it's super-portable for the example.

Thanks! I am trying to keep everything in one case for convenience. That said, That 42hp case is really cool! Looks like it could even be run off a battery pack, which is awesome. I'm getting a 3rd row Rackbrute 3U in a few months, so that'll work great, I think for drums/sequencing..

Quite, with more space in the 3U, you can even construct a drum source or two. Just trigger an EG set for a really quick envelope, feed that to a filter which is filtering a noise source. By rapidly modulating the filter with an exponential envelope with a very short duration, you get those 'filter snap' sounds ala 'Computer World'-period Kraftwerk that sound so GOOOOOOD!