A treaty-era battleship razee would make a poor cruiser

Could a treaty-era battleship be razeed into a super-cruiser or battlecruiser?

Not effectively; it would retain battleship-scale weight while becoming severely under-armed for its size.

Cutting down a battleship would not create an efficient super-cruiser. The hull and machinery would remain far too heavy for the new armament. Instead of gaining an economical cruiser, the navy would inherit an unusually large ship that was badly under-armed for its displacement. Successful age-of-sail conversion logic does not automatically transfer to steel capital ships.