I would reconsider the Octogain: it's a ART/Polytip (or whatever they're calling them now) module, which is meant to integrate with other Tiptop modules from the same line so it's kinda wasted potential (and it hasn't been officially released yet). If your main signal path will be morphagene->effects then you only have one pair of stereo outs to worry about and 8 mixer/vca channels seems kinda overkill. I'd definitely look into a smaller mixer/vca combo and add another modulation source/utility. A matrix mixer would also be really powerful in this rack because you could redirect the flow from one effect to another, feed them back into themselves and reorder your signal path. Looking at the Rabbit hole, it's a summing mixer, so be aware you'd be losing the stereo image from Morphagene and your effects (find a way to do parallell processing or an alternative stereo saturation/grit module).
How are you planning to integrate the drumbrute?