After a lot of trials, pairing, experiments… I present you the v2 of my studio case:
I ditched the OPZ as it was a pain to make it work in the setup, and crashing too much so I don’t trust it for a live setup, and causing USB issues. I also removed the NTS-1 as it was a productivity killer, with too much to experiment with (custom osc, fx…) and no save.
Syntakt was the missing centerpiece, and now that all digis have foldable keyboard with scales, I don’t need the Korg nanoStudio. I was also quite rigid to configure, with no ability to switch midi channel on the go and requiring a computer to setup.
Also added for welcoming additionnal controls, the Faderfox EC4: entirely configurable without a computer, with great flexibility and multiple switchable setups, it’s the perfection compation to the Bluebox and for adding direct performance controls (MW macros for the digis FTW!).
The extension box is still here to allow plugging extra gear with midi in/out, USB (w/ midi) and audio in/out. Only the sync out was lost due to ditching the NTS-1.
This setup is now stable as I made a lot of battle tests to ensure stability, ergonomy while keeping focused enough to be productive 
For the curious, I took a WIP shot while I was rewiring almost everything in the bottom layer:
Here are the routing details for power, audio and midi:
Power routing
Audio routing
Midi routing
Now if you excuse me I’ll be off for a few months to work on my live set…