+1 on farkas's comments above, plus consider: if it's difficult enough to do a single build function in a 1-row build, you shouldn't even THINK of trying to jam a second function in there.
Stop now. Back up a bit and do TWO different 1-row builds...one is the monophonic voice itself and the other is the electric bass FX chain. This time, also, consider your space carefully and, if you can jam in modules that have multiple functions (ie: instead of one ADSR EG in 8 hp, jam TWO in via a Doepfer A-140-2. Or have two AD EGs with their own VCAs with an A-142-2...that sort of idea), do so. Make ABSOLUTELY SURE that you're optimizing space vs functions like that when working small!
Then once you have them all sorted and optimal...mash 'em together. Obviously, this'll require a bigger case, for starters...but moreso, you can start to identify redundancies, eliminate those, and add MORE NEW functions that both signal paths can share.
One caveat about the audio input: definitely get something with an envelope follower. Bass is pretty expressive, and with an envelope follower, you can output voltages based on incoming amplitude and, if you want a real "peeeeoww"-type hit when you pop strings hard, that'll be the thing that gets it out of the VCF for you. Doepfer's A-119 is something of a workhorse module for this exact reason.
And, of course, VCV Rack is super-recommended as a way to wrap your head around the whats and hows of modular before dropping big buxx on hardware: https://vcvrack.com