Not sure. I googled "pulp molding" and saw a number of pages on things like egg carton molding machines. But, solidifying a whole block seems tougher.

Yeah, typically the issue with molded paper pulp is keeping a uniform wall thickness otherwise the moisture is trapped and you have a crusty object with a slushy inside.

Could they build it in layers? Or is the best way to do that to just do gluing, so it's back to the original idea?