> If the solution were technical we would need a combination of 2 and 3. Distributed hidden services. Is this even possible?

It is possible.

> The problem with technical solutions is basically Child Abuse Images.

This is a fake reason which is only used as a justification for censorship technologies. In practice it's better to allow distribution so that it happens in the open and new images can be discovered sooner and traced back to the perpetrators who created them. If you shut down a distribution network every time you find it then the only ones that exist are the ones you don't know about, which means you have no source of evidence to make cases against unknown active pedophiles.

The FBI had a successful campaign where they quietly seized a distribution server and then continued operating it so they could collect evidence and make cases against those using it. Naturally the headlines were "FBI distributes child pornography" rather than "FBI arrests many child pornographers" as though preventing distribution is somehow more important than arresting the creators and rescuing the children.