I just have a few quibbles or questions for you.
1) You mention Carnap in connection with the distinction
between physical and epistemic/logical/evaluative probability.
Others specifically say he originated the distinction. However,
Ernest Nagel already made the distinction in his 1930s contribution to
the Unified Science encyclopedia. It would hardly surprise me
to find that the distinction goes back further -- e.g., to
Pascal or somebody way back when.
Also, Carnap explicitly interpreted his logical probabilities
as strengths of belief -- although this may have only been in
the 1960s.
2) I haven't reread Ramsey recently, but as I recall he made
no suggestion that there be no further restraints on probability
beyond the axioms. (I may simply be misremembering, though; one
tends to read & remember people according to one's prior beliefs, of
course.) De Finetti, of course, did.
3) I don't think your explicatum cuts it, as I believe I
made clear in my dissertation. I await your refutation.
Please correct me as necessary.
Many regards, Kevin