If you want to speed run? Sure. If you want to just clear it, you can probably get away with less. But you have to find lower teams for that. Like something Momoi, Midori, Cherino and Iori with some support like Ako and Himari or Ako with Casual Saya or Karin. You have to get creative. You can also run as many teams you want to.
Thanks this made it very easy. For people struggling make sure to follow Valiants exact formation and what order of EX skills to use in the video. Also it's good to have Himari's weapon at 2 stars as that gives her Ex skill duration a longer buff. Make sure your main party have equipment at level 8 and if your characters are dying too soon it's probably cause they are not high enough star level.