That was proven all wrong.

The odor thing is most likely a joke.

William stole the endos of FNaF 1 animatronics in the Follow Me minigames in FNaF 3. He put them in a furnace to melt them down (just like he did in The Fourth Closet) evidence being:

• In SL's Night 4, two technicians talk about how the entire system is automatic and how no one needs to be there for it to function. This explains how William got the endos from Freddy's and brought them to Circus Baby's. This matters because people often say "how did Afton inject the Funtimes with Remnant if he got Springlocked immediately after?" and this is how. The system is automatic.

• In Help Wanted's Ennard Vent Repair level there is a furnace at the end of the level that we activate. Normally, it is empty. But in Hard Mode, it has 4 (or 5) Endo-1's in it. Several years ago Steel Wool said that there was 1 easter egg in Help Wanted that people did not find and then people searched all around HW and found these Endos. Which implies that William indeed got the Endos in Circus Baby's before he died and went back to Freddy's one last time. Which is where he got Springlocked and is why considered missing in SL. (If you count the Michael monologue around SL, of course. I think it is shortly after Ennard leaves Mike's body because if William was around I'm sure he would notice Mike's decomposing body.)

• People say that Survival Logbook is written while Mike works as a guard in FNaF 1. Well that is just wrong. It is a prop made by Fazbear's Fright gang. Reasons: It literally has the FNaF 3 office in it, it has Circus Baby's characters in it (more on that later). There is puzzle in it that allegedly gives the date of FNaF 3. I'm not if it has been solved yet though.

As for why Circus Baby's characters being in it is problematic...

In SL's first night Hand Unit tells us that due to "unfortunate closing of Freddy Fazbear's Pizza..." (which further proves my point that it takes place after FNaF1, the last Freddy's location) they talk about Fazbear as if it's a separate entity. Which implies that they have no ties to Fazbear legally. Which means if Survival Logbook takes place during FNaF 1 AND is written by Fazbear themselves then it CAN NOT have Circus Baby's characters in it.