The funtimes were possibly created before the mci
With sotm we can speculate that, even though the designs used in fnaf 1 were the originals, the ones we see in fnaf two as the withereds were created, and the mci souls are still in there.
It's possible that the "withered" designs were made before the mci, and William just took their endos to make the funtimes, which would explain the endos seen in the Help Wanted game thing.
With this we can explain why the businessmen in Sister Location were "casual" to talking to William as "Mr. Afton", the previously mentioned endos in the furnace. Why Funtime Foxy and Mangle have the same origin name in some stuff, and also it would make sense for the "recent closure of Freddy Fazbear's pizza" because when Micheal goes, the mcia recdntñy happened. And also how it makes sense for Elizabeth to die in 1985 (a youtuber made this theory of her death using the slowed down numbers of sister location).
Added to this, it would explain why Michel wouldgpt ot he fnaf 1 and 2 locations and be fired for "odor", because he already got scooped and is a rotting corpse.
Sorry for any spelling mistakes I've made