if a mint does fractional reserve minting then noone will notice!
Yes, it has that in common with any custodial service. There is hope: https://gist.github.com/callebtc/ed5228d1d8cbaade0104db5d1cf63939
The liquid federation does provide a constant proof of reserves. This can prevent a slow rug pull but not a fast one. Of course it cannot provide the privacy that a Chaumian mint can provide.
When will this be in production?