It's not possible to contact the third party without logging into "their" account, which is a crime under the Computer Fraud and Abuse Act. The act of getting that contact info from someone else's account is precisely what the CFAA exists to illegalize.
by using your email address, they have entered you into this trust with them. As such, you have a claim to ownership of the account. The Computer Fraud and Abuse Act only covers accounts that do not belong to you, and being this one partially does, you are within your rights to use the account to contact the other owners.
That's a pretty novel legal argument, that you acquire ownership of someone else's computer account - that you have entered into a legal contract with someone who isn't aware you exist - merely because they typoed their email address.
It is so novel, in fact, that it doesn't exist.
Don't make up bullshit and write it in legal threads. You might deceive someone into thinking your bullshit is accurate.
