I'll probably just save my SAW fairy and wait for plats.

Black SAW isn't necessarily better since they lose the 1-second activation. With the obvious exception of characters with godly SAWs like Elyse or Aisha. But Nanaly/Berna lose out on their potential insta-deletions, while Karma SAW is outright terrible.

For plats, I'll probably get the most mileage out of Rikka or something first.

Lilia, Shiho, Noel, and Solano are pretty high on my list too.