Hello.

1. hivewatchers/hivewatcher accounts are part of the project.

The first one is almost entirely used for leaving comments related to reports/investigations.
The second one is almost entirely used for other types of communication

1. It means that the scammer has used dozens of fake phone numbers.

Introducing a fee is a good way to prevent scammers although I think that $10 USD is quite a high fee.

Probably $1-2 would be enough to prevent mass account creation by one scammer as it would be a too risky "investment" for a scammer unless it had almost guaranteed high auto upvotes.