#2
It should fit. I believe the FV-500 is around the same size as a wah pedal. The website specifies that a wah can fit.
The DD20 and TU-3 require 9V power and the board you are looking at supplies 9V power. It will work.

And ths is in no way gear building and customizing.
*reported for move*
..I was watching my death.