Both Gustation and Inferiority always apply to Mark during turns that target Ethan.
Edit: Not sure which card it is, but Mark plays it, Caleb chooses Ethan, the Player selects either of the transmutations, and then it bugs and applies the effect to Mark.
Second edit: It's always a Sublimation card, and it doesn't matter who plays it, but Caleb's the one that chooses Ethan. I just got a turn in which Caleb played it, Mark rejected it, and then Caleb chose Ethan, and the Gustation transmutation still applied to Mark.