Duellant der Schlichterin

A repartee ability resolves before the spell that caused it to trigger. It resolves even if that spell is countered or otherwise leaves the stack.

Auras attached to the exiled creature will be put into their owners' graveyards. Equipment attached to the exiled creature will become unattached and remain on the battlefield. Any counters on the exiled creature will cease to exist. Once the exiled permanent returns, it's considered a new object with no relation to the object that it was.

It doesn't matter if the creature or creatures targeted by the spell that caused the repartee ability to trigger leave the battlefield or stop being creatures before that spell resolves. As long as that spell targeted one or more creatures when it was cast, the repartee ability will trigger and later resolve.