

Coffin Smasher is doing the same on his a1 whenever he attacks with that - not tuning it, just taking advantage of it when it happens.

This means that before each first AOE, Nazana is trying to apply Atk Down. Those speeds aren't set in stone, but the point is that you're running 1:1 with the boss, with Sandlashed going first in the turn order, Nazana going second to last, and Odachi going last. Odachi at 171 speed with a 1 turn delay on a3. Sandlashed lead for the Def aura at 176 speed, delay a2 by 2 turns. With Sandlashed's buff extension you could do something like this:

Nothing really jumps out at me as a must-build team, but you've got some rares that could be useful - Coffin Smasher has Atk Down on his a1 which should have pretty good uptime (not perfect though) and Odachi can block buffs and give a small Def Up every 3 turns so you could make use of him without needing a ton of speed.
