No. The owner of AF is Chad Sandstedt, which is not a secret. bchad is a completely different person whose real identity is anonymous to the vast majority of posters. It is entirely possible, although IMO unlikely, that Chad has an anonymous account that he uses to post here, but it is not as bchad.
Of course there is. I used to run 2 boards back in the day and through IP addresses the mods found out a good number of people did. The most likely profile of someone with multiple accounts is someone who is active with one account but uses another one occasionally to stir $hit, start mocking/trollish threads or thrash others without ruining the online “reputation” that their active account has built.
And yes, the owner of a site usually has multiple accounts, especially at the beginning of the site’s existence. I know someone that started a message board and used many accounts while marketing his page. It gave the impression that is was active and attracted people to come back. As soon as the site was on its 2 feet and had close to a thousand members, he dropped his other online accounts and kept his main one.
I know of at least one individual with multiple accounts. He often flacks a certain review course (under one account or another). As far as I know, he’s a bit of a d-bag in real life, too.