Technically and legally the photos would be considered child porn

I don't think that has been tested in court. It would be a reasonable legal argument to say that the image isn't a photo of anyone. It doesn't depict reality, so it can't depict anyone.

I think at best you can argue it's a form of photo manipulation, and the intent is to create a false impression about someone. A form of image based libel, but I don't think that's currently a legal concept. It's also a concept where you would have to protect works of fiction otherwise you've just made the visual effects industry illegal if you're not careful.

In fact, that raises an interesting simily. We do not allow animals to be abused, but we allow images of animal abuse in films as long as they are faked. We allow images of human physical abuse as long as they are faked. Children are often in horror films, and creating the images we see is very strictly managed so that the child actor is not exposed to anything that could distress them. The resulting "works of art" are not under such limitations as far as I'm aware.

What's the line here? Parental consent? I think that could lead to some very concerning outcomes. We all know abusive parents exist.

I say all of this, not because I want to defend anyone, but because I think we're about to set some really bad legal precidents if we're not careful. Ones that will potentially do a lot of harm. Personally, I don't think the concept of any image, or any other piece of data, being illegal holds water. Police people's actions, not data.