Overhaul will die at the hands of the Playtime Co. Toys
While it does seem far-fetched, when it comes out how the Quirk-Erasing Bullets are made from the blood of a little girl, torn apart and brought back together, Mommy Long Legs will throw all pleasantness out the window and alongside the other toys, viciously dismember and murder Overhaul.CatNap will likely be an antagonist later on, but will likely use the League of Villains and any useful pawns to help re-create the Prototype
CatNap never liked heretics who worked against the Prototype. So, upon finding out a six-year-old boy was brought back as a toy using the Prototype's parts, CatNap will view him as a heretic who killed his God. And as such, the heretic must be killed.Izuku will summon Boxy Boo later on
Hey, I don't see why they're keeping him out of the story, so why not have him show up?- Because at this point, no one knows where Boxy Boo's true loyalty lies. Until the chapter for Boxy Boo comes up, he probably won't be summoned. CatNap on the other hand is fervently loyal to the Prototype.
Aizawa will find out about the Bigger Bodies Initiative and the Hour of Joy during the Overhaul Arc
It's no secret Aizawa was investigating Playtime Co. due to it being Izuku's home, albeit a weird one. So far, he knows that it was an old toy company that was shut down upon the death of the owner, but it was also able to make live toys. He would also find out about the Hour of Joy, the massacre of everyone in Playtime Co. Employees and civilians alike.