354.2. See rule 360. Passive Abilities for more information.
354.2.a. Costs that are replaced with other events by replacement effects are still considered paid. Example: A player plays Cruel Patron, which says "As an additional cost to play me, kill a friendly unit." They also control Zhonya’s Hourglass, which says “If a friendly unit would die, kill this instead. Heal that unit, exhaust it, and recall it.” They choose to kill a friendly unit during rule