Too much mixer in the mix there. Both the Lifeforms System Interface and the Erica module do (basically) the same thing. I'm inclined to say you should keep the Pittsburgh mixer, drop the Erica, and use that space for something else, as having those three more (albeit ganged) inputs on the Pittsburgh will be more handy for juggling several percussion sources. Not sure why you'd have the Dual Zeus, either...this is small enough that a single input/single PS setup should suffice.
Beats...well, changing out sound generators would be a start there. It'd make more sense to find something that's more in a rhythmic-element vein for the voicing rather than VCOs. One of those might just be sufficient here. Also, lots of electronic percussion utilizes what're called 'ringing filters'...filters set just below self-resonance and which 'ring' when some sort of impulse gets fed to them in various ways. Right now, there's just the 4075 in Studio's ARP 2600 redux, and that's likely to be a constraint.
DFAM: not bad. BeatStep Pro: better. Cheaper, too. And you get...lessee...(looking at one of mine)...eight drum gate outs, two channels of CV/gate/velocity, MIDI I/O, clock I/O, and a more complex and interactive sequencer for $250. No, it doesn't say MOOG on it, but what does a word sound like, really? The DFAM is more about what it can sound like, not so much its fairly-simplistic sequencer which won't go too far in doing elaborate rhythm patterns. Oh, and no memory for said patterns, also.
It's a start, tho...definitely needs honing in on the voicing, though. Fortunately, MG's got loads of Drum modules of all sorts and flavors to sort thru. One other thing, also...when starting out on design, always make the rack bigger than you think you need, because you'll gradually discover that you actually DO need it that big. Sort of a Law of Physics of some sort...