Ultimate Challenge 2, 7 Turns - Mario + Rabbids

Ultimate Challenge 2 done in 7 turns.

Characters:

Mario
Rabbid Peach - She has strong defensive and offensive abilities that are useful for this level. Heal keeps the team alive throughout the battle and Shield's damage reduction saves her near the end. Her Sentry is a strong offensive option that is used to defeat incoming enemies quickly.
Luigi - He has some of the strongest offensive tools in the game. These are needed to take out groups of enemies quickly. Steely Stare and one of his Sentries are also used to deal with incoming enemies faster.

Summary of RNG:

-The Lava Ziggy gets 2 shots on you at the start. The route is ruined if he crits. I don't know what odds are of an enemy crit, but both of them combined get in the way pretty often.

-Luigi and Rabbid Peach need to defeat Bowser Jr. In order to do that, they need to get at least one crit one of their combined 5 shots. This is a very low chance of messing with your run, but it's still possible.

-The Sentry used on the wave with the Peek-a-Boos and Valkyries needs to crit, which is a 60% chance.

-The Sentry used on the Bwah Trio needs to crit, which is a 60% chance.

-Boo spots after turn 1 are random. They may get in your way in various ways, it's hard to give a percentage with how much information we don't have.

Note:

-Skill Trees for Luigi and Rabbid Peach are uniquely tuned for this battle. Luigi just gives up Itchy Feet for his other Skill Tree stats. Rabbid Peach should max out her movement abilities and give her 500 HP. Her shield should give 80% weapon reduction while her Heal recovers 50% HP. Both abilities should have a 2 turn cooldown.

-Rabbid Peach uses Shield on turn 2 not to protect herself, but to reduce the damage from the Spooky Smasher so it's Vamp healing will be reduced if it does crit. (Assuming the Sentry on the Smashers doesn't crit.) It needs to stay under 100 HP to go down to a single dash.

-The Lava Valkyrie that survives the Sentry explosion is manipulated to go to a spot for a second Sentry to explode on the Bwah Trio. Each character's position on turn 4 scares the Valkyrie away from a unoptimal area. The same is true for the Hoppers to a lesser extent.

-The Sentries are a good way to get high amounts of damage on the grouped unearthing enemies while crippling them with Super Effects. However, the true reason why they're used is because defeating they defeat defeat enemies quickly so the next wave of enemies can spawn earlier. The Bwah Trio will not spawn until 2 of the 4 enemies in Peek-a-Boo and Valkyrie phase are defeated. Reaction shots were all used up last turn, so the Sentry is the only available option. This is the key move that brings this level down from 8 turns to 7 turns.

-The Boos will change how the level works and whether it can be done in 7 turns or not. They can complicate things by luring a character away from an optimal position, bringing an enemy to the center to make a Sentry explode prematurely, and bringing a Hero character to center just as the Sentry explodes. Some Boo spots ruin the run, while others can be adapted to and even used to your advantage. (Which Mario did near the end.)