It took a while and many efforts to get every single detail right but here it is !
The circuit (almost) worked at the first try, I had to swap a few wires and now it is functionally "good" :-D
Some corner cases remain but they are not critical. The panel alone is useless and the user must also look at the disassembler panel to ensure that the buttons send the right signals.
I tested the circuit with a dumb load made of tiny Glühbirnchen but soon they will be augmented with the disassembler panel. I'll have to make a proper panel for the Glühbirnchen because they'll be useful to configure the DIP Switches...