Roke Julian Lockhart Beedell

I’m evidently less familiar with XenForo than I realised when registering, because I didn’t realise that the display name was what other forums refer to as a username (for it's unmodifiable, by me): If that’s accurate, I want to replace it with “Roke Julian Lockhart Beedell”, instead. Can I?

Thanks.

I recently attempted to log into code.wildfiregames.com/auth/start/, but my credentials were incorrect, and my recorded e-mail address was apparently uncorrelated to any account. Why might this have occurred, and how can it be prevented? Irrespective, can it be reverted?