Feynite's work is something I fell into right after reading the original book years ago, and I deeply appreciated the gentler twist she gave the characters and how much fun she clearly had worldbuilding in Wishverse and her AUs. I haven't actually read the other two fics, even though they're fandom famous, but I've heard good things.

As for reading SVSSS: I imagine the canon characterizations might be a bit jarring if you're used to fanon, but I do think it's still a fun book, and over fairly quickly at four volumes! Might be worth it if you think you're going to keep reading fic for it, just to have that extra bit of context.