Re: Grounding & On board preamps
In diagrams like this it is assumed that they are all grounded together by being screwed into a pickguard with grounded foil or some other thing their housing sits in.
Which is, BTW, how electrically you are supposed to do it. No potentiometer manufacturer has ever intended to solder to the casing. The way to ground these in regular electronics is that the pots sit in a metal front plate which is all grounded.