Quick question: I'm designing a PCB for a Fuzz Face type circuit. If I use the Road Rage board to power it (pos. ground with -9V), is the power to the effect already filtered and rev. polarity protected? Put differently: is it still useful/sensible to incorporate those parts on the FF pcb?
Yes, you do not need to include any extra filtering or polarity protection. It's all on the RR PCB.