Yes you can flag alt accounts:

Can I also create a scammer flag for alt-accounts of the contract violator? Example: BetKing.io violated a contract, but BetKing Support, dean nolan and PocketRocketsCasino are his alt-accounts.

Yes, one of the victims can.

That certainly covers it! Cheesy

Thank you all.

Just wasn't sure if the other alts could only get a "type 1" flag.
Question answered, thread closed.