Okay, I got my Twitch/Wowpedia login to work, but it was super confusing.
I can login to Twitch using username Fandyllic, but after I login, it displays Fandyllic38325 (if I try to use this to login, I get: This username does not exist.). If I then switch to wowpedia.org, it tells me I need to sign-in at Twitch again which sends me back to Twitch where I try to sign in and is sends me to the Gamepedia home page. No I can go back to wowpedia.org and I'm signed in.
I'm shocked at how bad this is.