I don't know about consumer protection in CA, so I can't offer much help there. But it does sound like you have a basically good car that is suffering from some deferred maintenance and low mileage problems, none of which are huge if you intend to keep the car for a while:
Belts screech - probably the alternator. Simple adjustment.
Burns oil excessively - probably valve seals if the compression test was good. Typical on low mileage cars. Check around with good independent shops for replacement. Do frequent oil and filter changes to clean up the varnish build-up.
Oh BTW the emergency brake dosen't hold the car at all - have an adjustment done. Not a big deal.
Rear suspension - have new shocks installed.
Leak fuel, smell in cabin and hard to warm start - take this one back to the mechanic - he clearly did not get the actuator repacement right.
Air conditioning - beat the seller up on this one. Otherwise, admit that you should have caught it when you drove the car, suck it up and get it fixed.
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe