Reimu's Evil Sealing Circle only works the turn it's used, so you'd need to use it on the turn she'd use Petro Cloud. Petro Cloud is a Permanent Effect, so you'd need to make sure to choose that too.

Sanae's Resistance buff is fine for the debuffs, but Petro Cloud has a higher chance of landing, so it's a gamble.

If you got the Petrify Resistance accessory, you could also give that to Sanae and then use her to cure petrify with her permanent removal skills (assuming Sanae doesn't get hit through the 75% resistance).

I'll think of more after trying these.

Alice cover all also works, or just covering the damage dealer if Satori is nearly dead