I'm not sure why would that be fraud - who would be the defrauded party there? Offering wildly different conditions or prices to different customers definitely isn't fraud.

The other customers have no standing there, they have no relationship whatsoever that contract between the bank and another customer, they have no legal expectation to get the same conditions or to know what conditions other customers get. If the bank explicitly and intentionally lied that no other customers get so favorable conditions, that might be false advertising but I'm not sure, I'd expect a reasonable court to interpret that a bank "telling your customers you don't and can't do this" is exaggeration/puffery (i.e. permissible) and doesn't have to literally mean that they're not doing that for anyone, it means that they absolutely refuse to do it for you.

No.

A car salesman telling you they can't sell you the new Buick for $42,000, when they sold one to their neighbor yesterday for $41,000 is not fraud.

Yeah but if the salesman told you it's a brand new Buick never been driven that they've actually been lending out to friends and driving around?