First up I decided to go for Shauntal.
Not too much to say about this that the screenshots don't. Scavenger couldn't finish off Drifblim though, so she killed it with Acrobatics from Unburden. Golurk was faster than Ford and killed it with Hammer Arm, and I had Light Screen (from Liquidify) up when Chandelure came out, so I Yawned her to sleep and got the Quick Claw to knock him low, then Shipwreck (my last one) killed her, and I didn't use any items whatsoever.
I would be mentioning MVPs, but I only have those in runs where I don't use any items (even though I didn't use any in this one fight).
Then we went over to Caitlin.
Musharna was easy, Reuniclus I had to do mirror-match against, but my Special Defense was lowered so Alakazam beat me to the punch. Metagross killed three of my Pokémon but was confused from Scavenger, so I finished that off with rain boosted Scald. Gothitelle used Flatter on Shipwreck and made her last two easy after Trick Room.
Marshal was next in line.
As you can see, Liquidify did a majority of the work here. I only needed Caldera for Lucario, who killed that with ease because of Trick Room. I then had Toxiswirl finish off Conkeldurr from a bit under half with Giga Drain. Mienshao killed her with Fake Out followed by a critical hit Hi Jump Kick, then Liquidify took it from there with a Max Potion, Reflect and then TwistedSpoon boosted Psychic on the rest of his team. So yeah, he was definitely the easiest.
Grimsley was last up for the Elite Four.
This fight was harder than I thought it would be. For starters, I led with Toxiswirl in a bad matchup, Houndoom had a critical hit Crunch before I killed him with Earthquake in that shot, thankfully Toxiswirl's Petal Dance knocked Tyranitar to the point where he healed, allowing Ford to use Brick Break. Scrafty missed with Hi Jump Kick and took 50% health, then after Caldera Yawned him to sleep I lowered his Attack some with Liquidify, got Trick Room and killed him with Focus Blast. I missed against Bisharp, and he killed me because my Defense was lowered. Shipwreck got him below half, allowing me to have Scavenger finish him with Low Kick.
Finally, we came to the Champion, Iris.
Dear sweet Jesus in the name of Godforsaken motheruffing tap-dancing christ on a stick was this fight madness. To start, that Hydreigon killed Liquidify in one hit with a critical hit Dragon Pulse, then while I did get in Trick Room and do a bit less than half with Shipwreck's Ice Beam, she killed that with ANOTHER critical hit. I lowered her Defense with Ford's Screech before she killed me with Focus Blast, and I finished her off with Scavenger's Low Kick.
So I was out half my team before Aggron came out. She missed with Head Smash, then I did more than half with Low Kick before Trick Room faded. Then I was concerned about what she'd do next, so instead of killing her, I Max Revived Liquidify before she killed me. Caldera was slammed in one also, and Liquidify got in Trick Room, but Focus Miss was for naught. She was out of Head Smashes afterward, and I foddered Toxiswirl so I could Max Revive Shipwreck, who killed her (she would have gone first had Trick Room not been up, interestingly).
Lapras was a bit of a shake, I did get Cursed Body to disable Thunder, but she put me to sleep twice. Once she was no longer disabled, I safely got Toxiswirl in on Thunder and killed her from 11/16 with Giga Drain.
Salamence was the kicker, though. Toxiswirl died right away, although Life Orb and sandstorm were eating away at her fast. With Trick Room from Liquidify, I did get in Reflect (following a critical hit Earthquake), and once I was down to Shipwreck I had to revive Toxiswirl. Once we were both healed up to full (and my Defense was lowered from Crunch), I took one more hit before killing her with a critical hit Ice Beam (which may or may not have mattered).
Haxorus took over half from Ice Beam then killed me. With Toxiswirl as my last one, I didn't want to chance it since she resists Grass, so I revived Shipwreck again. She killed Toxiswirl, but Shipwreck barely lived from half thanks to Reflect as I revived Liquidify to be on the safe side. As I Full Restored, she hurt herself in confusion, then the sandstorm finished her off.
Lastly was Archeops. I used Trick Room after Stone Edge did more than half, and despite the Special Defense boost she was handed from Sandstorm, I killed her in one hit with a critical hit Scald to win the battle. Goodness, that fight was a mission and a half, let me tell you.
But with that, the Elite Four and Champion were defeated, completing the challenge!