Cloudflare would have to bring that suit since they were the ones defrauded. The site owners probably can't sue Cloudflare because of their contract. So the site owners probably have to go basic "tortious interference" and be ready to show actual damages.

No, if the site owners have been harmed by Flock + Cyble knowingly filing a false takedown notice then they can sue Flock + Cyble. If Cloudflare's reputation has also been harmed then they could sue Flock + Cyble as well.

Tortious interference with contract, cut and dry.

> Cloudflare would have to bring that suit

At first that seems pretty unlikely, but I could see them wanting to nip this in the bud so it doesn't become more common.