Well, I beat it. My team was:
Frankie the Arcanine level 65
Forrest the shiny Primarina level 54
Janet the Lilligant level 69 (heh)
Vahni the Dugtrio level 60
A random Jangmo-o I was evolving.
A shelgon I was leveling up ate up the last spot.
Then I also drew how the ending should have went with Lillie, which you can see in my art thread. Now, ONTO THE BATTLE TREE