hmm... I hope this is just a first pass at trying to design a modular synthesizer!
you are trying to do too much in too small a space without the support modules that are necessary to get the most out of the modules...
ie - too mnay sound sources, so missing a lot of useful (by that I meam necessary) things, particularly modulation & utilities...
I can almost definitely see what you're trying to do - 2/3 voices, some modulation, some sequencing an an effect... but it's fundamentally lacking... if you went and bought this - you would be seriously disappointed, not only because it wouldn't actually do the things you want it to, and possibly to the extent that it might be up on reverb (or elsewhere almost immediately), or in the closet gathering dust, but even if that wasnt' the case, because there's not enough space for the support modules that are actually needed to get it to do what you want...
modulation - one of the fundamentals of modular synthesis... modulate your modules & modulate your modulation... a single lfo is not enough!!
utilities: see my signature... more mixing - sub mixers for the vcos to mix them before filtering/further processing... and that's just really the beginning - I see how newbies fail at this - these components of a synthesizer are either hidden or just missing from fixed-architecture synthesizers, but they're way more important in modular than anything else, in lots of ways, they really take patching from 1:1 (ie patch cable out to patch cable in) to 1:N - patch cable out to lots of inputs - & in doing so multing, mixing and mangling those signals - this is where modular synthesis really shines, especially when combined with adequate amounts of modulation sources!!!
envelope generators... a lot of envelope generators - but only a single gate source (the sequencer) to trigger them...
sequencing - the sequencer is a single oupput... how are you envisaging sending pitch information to all the vcos? and is the same sequence sent to all vcos useful - it is if you're going to tune the lfos to intervals, but there's no way to create basslines & melodies that differ - so you can't for example play the root on the bass and a melody for a lead...
overall: take a look at my signature and specifically the formula - it's quick guide to how to get the most (versatility in patching) for the least expense & is scalable from the tiniest to the largesst conceivable modular synthesizer...
I'd also seriously recommend going to modwiggler and reading the intoductory pinned threads in the 1u & 3u subforum... and reading as many newbie threads as you can handle...
after that I'd recommend ignoring the size of the case - plan out exactly what modules you want (and those that you actually need to achieve your goals) and then build another rack here and get it checked... and then before buying anything work out the case you need to put it in - leave at least 20% free space - allow 10mA/free hp per rail... them allow at least 25-30% headroom on the power supply (to allow for inrush & potentially bad power specs)
then work out a minimal version of it... a single sound source, a single sound modifier, a single modulation source, some utilties and a sequencer etc and then buy those and start playing with it & learn those inside and out before adding more modules, slowly... and repeat... 1 or 2 modules at a time...
I know this sounds a bit boring, but it'll get you to a better place, quicker than anything else... & for less money!!!
good luck!
"some of the best base-level info to remember can be found in Jim's sigfile" @Lugia
Utility modules are the dull polish that makes the shiny modules actually shine!!!
sound sources < sound modifiers < modulation sources < utilities