Hi,
If I understand correctly, at Dice with Death, you can only spend 1 Fate for one of your own two dice, and you cannot spend any Fate to influence Death's dice.
Does the same thing apply to the Pitfiends at the Pit and the Werewolf at the Werewolf Den? I would personally think so, since the roll only determines how many Pitfiends there are and how strong the Werewolf is. Only after that do you engage in battle with them, and there you can spend your Fate.
At Dice with Death, you cannot spend Fate to make the challenge easier (the number you need to roll = Death's dice), but only on your own result (the number you roll yourself). It would make sense the same thing counts for the Werewolf and Pitfiends, that you cannot spend Fate to make the challenge easier (the strength you need to beat/the number of monsters you need to beat), but only on your own result (the number you roll in battle).
Is it correct of me to think that way?