I'm not going to try and waddle down the audit trail, just going to treat Tazz's last post as the real thing.

Raichu
Onix
Farfetch'd
Butterfree

VS

Farfetch'd
Nidoqueen
Venomoth
Primeape

Raichu zaps the bejezzus out of Farfetch'd. Win.
Onix earthquakes the stuffing out of Nidoqueen. Win.
Farfetch'd eats Venomoth for breakfast. Win.
Butterfree makes Primeape go flying like a kite. Win.

I remove Nidoqueen, but Mystic still possesses the gym.

Gym:
Farfetch'd, Venomoth, Primeape
Team: Mystic