If 2 Zonyas are in play, do they both trigger when a single unit dies?

Ruling: No, only one Zonya triggers. The owner decides which Zonya replaces the death.

Sequence:

• A unit would die
• Owner chooses which Zonya to apply
• That Zonya kills itself instead of the unit dying
• Since there is no unit death anymore, the second Zonya has nothing to replace

Nuances:

• Zonya doesn't trigger, it replaces the death
• Once the first Zonya replaces the death by killing itself instead, there is no death event for the second Zonya to replace