Ms. Myth is a "bonus" dossier, to give folks (with the Beginner's Box) a sample of a more involved character sheet. Hardpoint, Coydog, Sledge, and Gentry were the original intended dossiers, and are in the product that originally intended to host said dossiers (the more involved/intermediate box). Remember, the two boxes are (when not digital) being released as separate products.
Coyote's listed as a Mentor Spirit (for those with the SR5 core book) using the stats for Raven. As for the lack of Mentor Spirits in the Toolbox, I've shot an email upstairs to see what's what, FWIW.
I'm not sure who wrote the "crunch" bits in Plots and Paydata. The fiction itself ("Mischief is my Business") is mine, but I really don't recall who did the "By The Numbers" parts.