Yes, simultaneously should not be a problem.
CC16 is total FX1 block ON/OFF, fx1 being boost/mod section (also knob in katana);
CC17 is total FX2 block ON/OFF, fx2 being delay/fx (knob on katana)
So, to activate for example delay you need: CC17, delay_on, select delay from select delay or fx. To doublecheck this you can select fx off.
Is this making sense?