Ok, so the Dust Wight variant (+1 CR): "and when it hits a foe with its slam attack, causes the creature struck to become dehydrated if this victim fails a Fortitude save (same DC as the wight’s energy drain attack)."
Does this dehydration effect:
1) stack with the wight's normal (1 Level, DC 14) energy drain, requiring 2 Saves for each of its slam attacks
2) replace the wight's normal energy drain entirely as a different effect
3) be selectable on or off with the normal energy drain as something it can select from
My guess is that its not #2, as another Wight variant, the Salt Wight, specifically says, "Salt wights have the desiccating touch special attack, which replaces a normal wight’s energy drain attack. But its also not spelled out like another variant, the Frost Wight which specifically states 'in addition to'; "Frost wights have the cold subtype and their slam attacks deal 1d6 cold damage in addition to the normal effects."
Related question: its possible to combine variants so long as their ending CR 'fits'; in my case this would be for a 6th Level Cohort and based upon both backstory as well as what has happened the past year In Game, the perfect cohort is Mist & Dust Cairn Wight. Which sounds wacky but fits roleplay wise as well as math-wise (CR 4 for a Cairn Wight + 1 CR for Dust +1 CR for Mist) assuming variants can legally be combined like this.
Any help would be appreciated!