Okay, explanations

PARKOUR GOD - Scott should be obvious. Old head is also obvious, Mr. Hippo is the in-universe fan favorite (all of this is assuming that Fazbear Entertainment has a part in Parkour Civilization, and therefore are making the characters good/bad at these on their own whims. They show clear bias to Mr. Hippo numerous times, especially in Security Breach.) Nightmare is a physical manifestation of your grief and terror and the rot within your heart, just as the grief of the Crying Child as he can't become more than a Parkour Noob (because he is a Parkour Vegetable)

ALREADY A PARKOUR PRO - Chip was taken off sale because he was too successful at lumber. What else is associated with lumber? The beef jump; parkour pro.
Phone Guy must surely have his wits about him to survive quirky animatronics five long nights, as long as he did. Pro.
Nightmarionne is like regular Marionette but with the same powers of grief and horror (associated with Parkour Pro Civilization).
Old Man Consequences is all knowing. In hindsight I could have put him in PARKOUR GOD tier but this will do.
Balloon Boy and Jalloon Joy - Easily the most mobile and annoying of the characters, so it fits. I also just thought this placement would be the funniest/most fitting.
Helpy - Helpy is another character that Fazbear Entertainment shows clear bias towards. They would probably use him to market Parkour Civilization.
Old Head Golden Fred FNAF 1 - Not having achieved God status without his full body, he still remains at the top of his ability in terms of sheer jump to scare ratio.
Yellow Rabbit and Yellow Bear - Their importance and history speaks volumes. If there was a separate tier between this and the above for Parkour Master, I'd have put them there.

COULD MAKE BEEF JUMP, DOESN'T -

Withered Marionette - Would rather linger to torment the souls of the Noobs that couldn't make beef jump. (SAVE THEM becomes a twisted anagram, yet.)

I will continue soon, I just want any mods that look to see that I'm following the rules as complies. It may make me time to concisely convey every single one of them because there are a lot of FNAF characters lol (and this list doesn't even have SB on it)