So, thinking about it a bit, I've come up with this. More experienced users please feel free to fix what's lacking/wrong!
First off, little known secret is that the 6U Rackbrute is actually 89 hp for some reason (at least, mine is). Blessed be extra hp.
I've tried to keep all of the modules you already had, except one, since I assume you already own them. I've removed Brains because it's big for what it does, and switched in a Klavis Twin Waves MKII which sounds awesome and is much smaller. All other modules are kept, but rearranged (my own preference and workflow reflected here, nothing particular about their arrangment).
Top row has Pams and the PPEXP-1 which gives you dedicated outs for regular clock, allowing you to do more interesting rhythms or voltages with the original outputs (including random, smooth random, quantized, logic, euclidean, etc...). Then your oscillators, followed by a gnarly dual/stereo filter, the Ikarie. I finish off with your envelope generator and FX.
Bottom row adds some random flavor - the highly compact Tagh to give you random voltages, the SHTH to help pick off voltages, LFOs, and a 2hp VCA, since modulating modulators is fun and you had the room to spare. Your sequncer and more LFOs follow, then the mult, 6 chainable attenuverters, and then the uO_C. I found that getting an uO_C was the primary stepping stone into generative. The shift register and quantizer are just a delight together. The other utilities presented will give you a taste of what else is out there and how to use them, so if/when you get a bigger system, you'll already have experience.
Then the Frap Tools 321 for more voltage/audio futzing, then your VCA, Mixer, and Outs. Eezy peezy.
It's not perfect, but it's a start towards generative so you can decide when you want to do with your system when you (inevitably) expand your system. Should be fun to play, at least.
Best of luck!