I made a Google Plus account for my business a few years ago and now I need to edit it.
I tried all my Gmail accounts to retrieve it, yet none of them work. How can I find the correct email used to create the account so I can edit or remove it?
In Google Contacts, when you add a Google email address to a contract, it will show you the connected Google+ profile, if there is one.
So just add all of your Google email addresses to one or more contacts and watch for the connected Google+ profiles.
You might try to send a message to that profile and see what email address receives the notification.
One way is to create a G+ post (with another account, obviously) and share it only with the profile you're trying to reach.
There's also, depending on settings, a "send message" icon displayed under the profile picture.
Or you might simply add the profile to a Circle; there would be a notification sent about that. (This also depends on privacy settings, but it's on by default.)