For smaller systems, I find the Intellijel 7U case neat, as you can use the extra 1U tiles to take care of the I/O module and some other features, such as an Audio/CV mixer (Quadratt), a step sequencer (Steppy) and other neat utilities. Keep in mind: only Intellijel 1U tiles will work in that case.
The Erica EG/LG is neat, but you’ll get way more bang using a XAOC Zadar.
Devoting that much space for a mixer in a system this size seems like overkill. There are smaller solutions from the Erica lineup (Fusion mixer is nice, as it has a pleasant tube overdrive and six channels).
I would also suggest to have a more performance oriented sequencer, especially for live performances, same for your clock. Tempi is hard to beat with it’s UI and a Varigate is much better suited for per step changes. Manis Iteritas is great, but not well suited for per step on the fly changes, albeit loading from one of 16 banks can work. Rene is big, but really outstanding (MKI going for $350-380 now). The Trigger Riot could be a neat option as it’s a clock/gate/sequencer unit, well suited for performance in mind.
If it was me, I’d go 7U, Quadratt as mixer and I/O in tiles. Another tile for noise. Trigger riot, Zadar, Quad VCA, Tallin Dual VCA w/drive, Maths (if you must), Logic Module, and then fill ‘er up with sound sources, filter, wave folder etc