Here we go...I not only aimed to make this build modulation-centric, but I added a Doepfer A-119 so that you can pick that bass up again, plug it in there, and have both the audio from the bass PLUS envelope extraction for another modulation CV.
ModularGrid Rack
No, I didn't stick with Doepfer, but the overall cost seems to be about right for a 1-row device. Lots of stuff got switched around, in some cases in deference to other similar modules that do these things better, and in others just to build up a good, versatile modulation skiff. I did remove everything involving clocking, as there's no sequencer in the build. But this gave me room to seriously punch the modulation capabilities up. Here's what's there...

First up is the A-119. Then the Doepfer Noise/S&H, then an Intellijel Bifold, which can work either on the bass input signal, or it can be used to mess with modulation signals. Quad LFO after that, then the Mixer got repurposed so that you can create composite LFO signals.

Then Maths. By putting that in, I was able to remove the ADSR/LFO and the Delayed LFO because Maths can do that...and buttloads more! And it even comes in at a lower price than those two Doepfers. After that, you have a Happy Nerding 3xVCA to control modulation amplitudes, and a Frap 321 for mixing, attenuversion, and a few other tricks for creating complex modulation curves. Plus I added a Quadrax/Qx so that you can have four EGs there which can also be used as looping EGs for extra LFOs, and with the Qx you can cascade EGs in various ways based on whether you choose the EOR or EOF triggers to fire the next Quadrax stage. And last, I put in a Happy Nerding FX Aid XL so that you've got an extra stereo FX processor for signals coming off of the Nyx, or you could use it for your bass audio.

Now, I'm assuming that this is for a powered cab, since I didn't see any P/S in the module complement. If you DO need to add a power supply, my suggestion would be to pull the FX Aid XL then add a 4ms Row 25, leaving 2 hp open for something else. The 4ms supply is more than adequate for this, if necessary.