@ Faderboard 1 & 2
Mounting holes labeling not necessery again.
rest is ok.
you may could label + and - beside the 2x5 shroudet Pinheaders, so there is no chance someone reverse it in a way... in generell... normally the Nose- says all, but someone could crimp the cable incorrect... so if he controll measure, this is a good hint then for him.
@ pusbutton:
the LEDs in the shematic are REVERSED
for example look into: http://ucapps.de/mbhp/mbhp_doutx4_32leds.pdf
but in the board itself the Silkscreen for the Diode is painted correct - so if somebody just solder the PCB without looking into the Shematic - all is good, when someone look into the shematic he may be confused a bit.
what type off Switch are using here > type it on the silkscreen - like you did on the Potentiometerboard.
because: i see in the footprint its a le mec > then there are different types, with different Switch contacts - like you see here:
5GTH9 + 5ETH9 will work, while 5GTH9 with inbuilt LED will not work off course...
i for me find the correct switch matching to your PCBs Footprint-Pinout - a bit hard... so label the type....
the rest off the PCB looks ok.