There isn’t really too much to worry about for challenge stage 3 of this event, but it does have a slight gimmick of having enemies spawn behind the team. We highly recommend bursting down both Momoi and Midori to ensure your backline can survive.
Team building for this stage is relatively simple, bringing along both Explosive AoE and Single-Target damage dealers to make quick work of the enemies in this stage. For lower investment teams or newer players, we highly recommend having a tank to soak up the damage from B.Toki + M.Aris and a Healer to keep your backline healthy since Momoi and Midori will be spawning from the backside. Once you have the core roles for the team filled, feel free to bring along general supports as needed.
Note that characters listed here are only some of the viable options