Well, several things come to mind. First up, is MIDI necessary here? If the idea is to mainly drive this with a Dark Time, you're better off connecting it via CV/gate to the modular and losing the A-190-4. Also keep in mind that the Dark Time, if I remember correctly, contains pretty much the same MIDI-CV converter, making the module redundant. Second, there are far better alternatives to that A-145 LFO that offer CV control...or even more LFOs...in about the same sort of space.
VCOs...OK, let's say you want to run the Dark Time in 2 x 8 mode. Now, having just one VCO is passable, but really you want two VCOs so that you can use techniques such as detuning, oscillator sync, and the like. So with two different lines at once, what you'll want is four VCOs...which might sound like a huge space-hog, but there are quad and/or dual VCOs out there that will give you what's really needed there in a decent amount of hp. In fact, a pair of Klavis Dual VCOs would do the trick and give you quantizing for your sequencer CVs all at the same time. After that, you'll need a mixer to sum your VCOs down; if you want full duophonic performance, you need a dual mixer to sum each pair separately, but if you're OK with feeding the two parts through the same filter (usually referred to as "paraphonic" voicing), one that can handle four inputs summed to one is just fine.
Filter choices aren't bad...the Wasp clone will have that dirty sound that the original was known for, and the SEM filter is sort of a clone of the original Oberheim state-variable. However, having just one envelope gen is a problem; with two different VCFs, you'll enjoy having a different envelope for each, so that the timbre can "morph" in a sense as EG 1 gives way to EG 2. But even with a single VCF, you'll still need more EGs because you'll certainly want different envelope curves for your VCF(s) and VCA(s).
Noise/random gen: good. But you'll want some sort of sample-and-hold module to make even better use of this, by 'freezing' random values as discrete CV levels to use elsewhere. If you go back to the middle part of ELP's "Karn Evil 9, Impression 1", that bubbling-on-one-pitch sound is done that way, by feeding a sample-and-hold to the filter that's in the patch. S&Hs have a lot of uses, and are very much as bread-and-butter module. You can also clock this via the Dark Time's clock, which would then sync up these randomized changes with your sequence timing.
Multiples: not in this. This build is too small; even a 2 hp mult will be better left out in order to make that 2 hp space available for some active functionality. Instead, use inline mult "widgets" that several manufacturers have available.
Lastly, the end of the chain. While the Quad VCA is a great choice for both mixing and enveloping the VCFs' outputs, plus leaving a couple of VCAs handy for altering CV/modulation levels (which is another reason for having more LFOs and EGs), that shouldn't be your final module. The output level will still be at synth levels, and optimally should be backed down to proper line level before leaving the cab. Also, you're missing any sort of reverb, etc at the end, post-VCA...this was a huge part of why the ARP 2600, as one example, sounded as cool as it did. No room for a proper spring here, so a spring emulator like the Purrtronics Purrvrrb would be ideal, as it's small, PLUS it's a mono-in, stereo-out device, giving you a nice, wide stereo image. Couple that with a stereo balanced out with a level control such as Happy Nerding's Isolator (which also has transformer balancing and isolation, helping to avoid noise issues, ground loops, and other annoyances), and there you are.
That altogether would be a lot more solid...and still, if done carefully, will fit just fine in the space you've allocated.