For me, with a similar wildcard setup, it became something I wasn't willing to spend money on. I work on the basis that accounts are compromised and if the company is large enough I'll see it in the news. Strong passwords, and a password-database is the best I can manage.
You can have haveibeenpwned.com check for the custom domain itself. For instance, I get notified if any email of our family domain get leaked (not just mine).
Yes, but note that you have to pay for that, see the pricing here:
https://haveibeenpwned.com/Subscription#corePlans
For me, with a similar wildcard setup, it became something I wasn't willing to spend money on. I work on the basis that accounts are compromised and if the company is large enough I'll see it in the news. Strong passwords, and a password-database is the best I can manage.
You don't, you can register a whole domain and it'll work.
One by one, but I think the question is about the entire domain name
You can have haveibeenpwned.com check for the custom domain itself. For instance, I get notified if any email of our family domain get leaked (not just mine).
If you sign in that's an option on your dashboard. You need an account because you need to verify the domain is yours