From FNaCoso 2 minigames we saw First location befor Cosos 1. In my opinion its same as from Coso2. Heres reason :

If wee can see, we have 2 doors. Left is exit, right is maybe Backroom ( Just like FNaCoso 2 map). From First teaser of FNaCoso 3 we can see Cosonet without faceplates. I think he was one of First robot. Old Coso is that robot from minigames. He Looks very familiar to that from " our magic World" teaser. In my opinion Old Coso i Cosonet was First robots. Maybe place was closed down cuz maybe Old Coso bite a Child ( check night1 minigame). Thats all for today.