If I have Togekiss with "Wonder Kiss" Ability in play and my opponent's poisoned Active Pokemon only has 10 HP left, do I take an extra prize when it is KO'd during Pokemon Checkup if I flip Heads for "Wonder Kiss"? What if Togekiss is in play and my opponent's active Pokemon knocks itself out?

The KO can be during either player's turn or during Pokemon Checkup, and it doesn't have to be from an attack. Wonder Kiss only looks at your opponent's Active Pokemon.

Relevant cards

SV8_72