Formation is okay, back two other meaning are not okay.
Sankhara are coworker originators.
Sankhata are lucky men or victims.
Every aggregates must be many cause states (conditioners) and many effect states (conditioned).
There are only two unconditioned, Nibbāna and Illusion (Paññatti, included name).
Nibbāna, a reality, is not conditioned by any Sankhara because it is the cessation state of Sankhara. It is the opposite of conditioned. Whoever , aggregates, knew Nibbāna must going to never born by conditioners again in 7 births. It is never arise but it is still a state either one know it or not. And who want to know this reality must practice hard follow the Buddha only, except SammāSambuddha and PaccekaSambuddha.
Illusion (Paññatti, included name) is not conditioned because it is just imagination which must imagined by someone. It is not reality, not truth. And it is not the opposite of aggregates because erything, all aggregates, Nibbāna and all Illusions, can be imagined by thinking (mind;Cittu-Uppāda).
See Abhidhamma, especially Patthāna (24 conditions), for more information.