"I don't know if the images/videos in question could be argued to be erotica, and not fitting the federal definition of CP."
A good point. The bar for erotica where minors are involved is incredibly low. It doesn't have to be explicit hardcore, it doesn't even have to be nude. And the room for interpretation when the defendant himself admits to having sexual thoughts about children...
He's hammering the nails into his own coffin.