1) No, it doesnt mean passive volume pedal=tone loss. If thats the case, no manufacturer will be producing passive vol pedal. Theres lotsa talk about tone loss and most of the time, reading it extensively online often make one hear tone loss even before having the gear and playing with it.
2) Buffer exist for a reason, some people doesnt like how buffer changes the inherent characteristic of the sound. Again, some can hear it, some cant. And matter of fact, depending on the pedals we have, in our setup, some has buffer as part of the circuit itself. If theres another pedal in the setup with buffer, its good enough to ensure that the signal integrity aint compromised. Theres no need to add another buffer in there. It aint a more buffer, better it is situation btw.
anyway, forget bout tone loss for a while, go for the one that you want most. Ernie ball volume pedal is almost like a defacto standard for passive volume pedal, if it really cause tone loss, no one will be using it.
and if the visualsound one coz of the buffer, can solve all "tone loss" issues, everyone will have one on their board.
imho