Today I defeated Red in Ultra Sun's Super Multis with a team almost identical to
Echskiry's, but I lost midway in my first try due to HAX since Mimikyu failed a Play Rough on a Porygon2, which procceeded to paralyze it with Thunder Wave and, if it wasn't enough yet, it even lowered its Sp. Def. with Shadow Ball. I really hate miss moves, so in my second try I replaced Ghostium Z by the brand new Mimikyum Z, and this time it worked wonders ignoring Play Rough's 10% chance to fail. It OHKO'd things like Lapras at +2 and left others like Avalugg with its HP in red, easy target for a boosted Shadow Sneak.
Now I'm trying to get the Super Multis' stamp. The trainers I've recruited so far are promising, like Cynthia or Anabel, but some set or ability in some of their Pokémon are not the best to work with. Most decent guy I've found is Cook Julien/Sly, which leads with Scarf Typhlosion and then Air Balloon Magmortar. I remember some of the records in XY's Battle Maison's Super Multis included Scarf Typhlosion on the AI's lead, so I'm trying to support it with Mega-Charizard Y (Heat Wave, Solarbeam, Dragon Pulse, Protect) and Garchomp (Swords Dance, Dragon Claw, Earthquake, Rock Slide). The latter currently holds a Lum Berry, but I wonder if I could use Groundium Z? Just to prevent hitting Typhlosion and Magmortar once if the Balloon is broken. I wish I had a better fourth Pokémon than Magmortar, but it should at least also benefit from Drought.