chey i am sorry to do this again haha
Somewhere I still have an old document I'd typed out about the candidates for Mysterion and who was most likely to be, from an old blog at the time.
Me and @muttsterion had a lot of discussions at the time. She was positive it was Kenny and I was like, "I want it to be Kenny, but I'm just not confident in Matt and Trey enough", and I was wrong and very happy to be wrong about this. We actually started a Coon and Friends-style fic before the episode aired and then adjusted plans.
A then-friend told me at the time she and her tattoo artist thought it was Kenny, which always sticks in my head as a funny anecdote.
A lot of people did think it was Clyde, because he falls asleep during Cartman's presentation and some people thought this was a 'clue' he had been up all night as Mysterion.
One of my friends planned out an elaborate, epic-length fic where it was Clyde, and gave him a dark backstory, and ended up losing interest in this as a fanfic and repurposing it for some original fiction. For him I think he viewed Clyde as a blank slate.
I recall vaguely a fanfic with Craig!Mysterion and Kyle at the time, but not much details. This was the main instance of Craigsterion I saw at the time. I got the vibe some people liked the concept but nobody thought it was the canonical answer, especially because "Pandemic" had just happened and so "nice and boring just the way I like it" was right there, and "Fishsticks" also reinforced this attitude.
I also remember a fanfic where Kenny claims he's going to fuck Mysterion, no matter who he is, to which someone points out he might be Mysterion, and he's like "then I'll fuck myself if I have to!"
I don't really ever remember anyone who thought it was Stan, but I think a lot of this was that Stan was such a main character I think subconsciously a lot of us felt like we'd KNOW if it was Stan. One of the main Stan fans I knew at the time gave him his own hero identity, as did I, although mine was.... very Mysterion 2.0-y.
For a dark horse, I drew Pip as Mysterion at one point and SPS included Dogpoo in a poll for Mysterion's possible identity which I found funny.
When "Mysterion Rises" was about to air, a trailer consisting of Mysterion's opening monologue (including "I do have a power...") was released alongside the poll I mentioned, and Kenny won by a landslide on the poll. I'm not sure how much the trailer might have helped.
Oh, and between "Coon 2: Hindsight" and "Mysterion Rises", there was speculation, too. Some people expected Mosquito to be Kyle because of the lemon bars and doing good deeds and standing up to Cartman (bummed this was COMPLETELY dropped once we found out it was Clyde) and some of us thought Mint-Berry Crunch might turn out to be Kenny. I really really did not like the idea but I felt sort of resigned to it. It sounds silly but I was very deep in "Matt and Trey won't let Kenny be cool" until that point. A few people thought Bradley was Human Kite because of the lower pitch and lack of dialogue. (Yeah, the fact it was setting up a joke about a Jewish slur was something a lot of us guessed, too, and some didn't want to buy.)
I will say one reason something feels slightly lose in the later Coon saga when they sort of just accepted we know who's who now. There was a lot of fun magic in not knowing who everyone was, the creativity is lended toward, and the heroes kind of feeling like unique characters, but it does feel like by Fractured but Whole, they were pretty resigned to letting them be kids in costumes, which sometimes worked really well and other times was... okay, I guess Mosquito's at Raisins now. Very heroic, very demure.
