It's possible that Saki is a 'villain' in a different way, regarding her back story I mean
Like, maybe she was very, very jealous of wheelchair girl or something. Definitely would be a big plot twist away from the cute & innocent thing.
Rinkai is most likely going through, especially now with Mako's "unfinished business" with Hao, but yeah, I can see Kyouko thrashing everyone at the end though. Like, she just barely finishes 3rd, but scares the living crap out of Saki. There's just too much good build up in her character to not make a huge dent in the story.
But if Himematsu actually goes through, then I could see the final really being between Saki's power vs. Kyouko's crazy 'normal' skills.