Regarding your latest OK KO theory: Venomous actually does attack KO (along with Enid and Rad) with the cannon/gun thing in "We've Been Captured". So he isn't caring towards /all/ children.
While I agree that shooting a giant pie at a child isn’t exactly nice, that the scene used the pie-to-the-face gag at all makes the “attack” funny. If Venomous actually wanted to harm them, the scene wouldn’t have been played for laughs. And Venomous doesn’t need to be caring towards any other children to debunk the “Venomous=Shadowy Figure” theory. He just needs to not treat them badly. Plenty of people dislike children in general, but would never beat one up, call them pathetic, etc. like Shadowy Figure did.
Venomous enjoys “squashing heroes”. He certainly had the power to seriously injure (or possibly even kill) KO and co. He had been in a bad mood the whole evening. Neither Fink nor Boxman would have judged him for hurting the heroes. If Venomous is Shadowy Figure (who has no problem hurting children), then why did he choose to not hurt them, despite there being no apparent negative consequences for him if he did?
@j-l-thorne pointed out that the pie was enough to launch the kids across the street, and Venomous wasn’t concerned about their landing. While this would obviously be an awful thing to do to to a real child, let’s consider that KO, a 6-11 year old, can easily lift things twice his size and shoot energy from his hands, Enid is a ninja, and Rad is an alien with psychic powers. They fight robots with buzzsaws and lasers on a daily basis, at their convenience store job. The building they work in stocks weapons and explosives, and rests on top of a magical maze. None of these things are unusual. The inhabitants of the OK KO universe are much sturdier than we are, so it’s not nearly as big of a deal as it would be in our world.
Additionally, Venomous found KO familiar. This will absolutely be significant later on. It won’t be something trivial like “Wait a minute, is that… the kid we happened to cross paths with at the grocery store that one time?” We know that KO is much stronger than a normal child because of this “dormant power” he has, which is likely connected to Venomous somehow. Venomous knowing about this power would mean he would be even less concerned for KO’s safety.
Thank you both for replying! It’s good to know there’s people out there thinking about my theories! ^v^