I have a Tactical Doff that gives a passive chance to reduce the cool-down on Grenades.
I'm an Engineer.
I can get Cryo Grenades from the Breen Series.
Will the passive have a chance to reduce the Cryo Grenade's cool-down or is it only for Photon/plasma/stun grenades?
I haven't had a chance to check on Ground Roster DOFFabilities . . . but for the Space Roster, when you put a DOFF on your Ship Duty list you can hover over the BOFF / Captain ability that DOFF modifies and see the actual effect listed in the info text.
For example, I put a Engineering DOFF with the ability "Chance to Reduce the Recharge Time of Enginerring Team and Auxiliary to Structural Integrity Field". When I hover over my Engineering Team in my hot bar it shows that I now have "20% chance to reduce recharge time by 20%".
If you have those Cryo Grenades, slot that DOFF and check the mouse over info window on your grande hot key while you're on a ground map.