He definitely could for defamation. He would literally ruin them.

I sure hope so

To sue these three journalists under defamation claim will require a massive amount of money for lawyers and court cases (unless of course, he win the case). But even if he win the case, I bet big companies like Disney and Google (Youtube) wouldn't bat an eye on the case. I think the most important thing now is to slowly build up his reputation again and reach out to brands for additional supports. Maker Studio is not the only network in the world, there's hell lots of networks out there available.