Tor will help you by hiding your identity so they will be in a dead end when they sue and try to find you.
And yes of course you can also use Tor to contact them anonymously before disclosing.
And yes of course you can also use Tor to contact them anonymously before disclosing.
Once you're in there you can just use the Tor browser to create an email account at any email provider (make sure you give them fake details though) and send your email.