Hm. So then do we have two types of problems you're claiming Bayesian inference isn't good enough for? One is problems involving freebits, and another is problems involving disagreements about reference classes?

The reason I don't think "Earth C" had an impact on the perfect-prediction-except-for-isolated-qubits case is because I'd turned the reference class problem into an information content problem, which actually does have a correct solution.

where it's not even obvious that there is a "true, pre-existing answer" out there in the world

I think this is the normal and acceptable state of affairs for all probability assignments.