Jump started, lights flashed, idled erratically. Took to dealer, replaced starter. Would not start next day. Now say it's the control panel...

Hello, there are no "codes" that will indicate any of those problems. Was the starter motor probably a guess gone wrong? Probably. Would it be likely that anyone could have guessed the control panel would be of concern? Doubtful. My best suggestion is that you could negotiate diagnostic charges as a goodwill situation or make a case for a good discount. But ultimately - it's your vehicle, there's no perfect scientific yes and no diagnostic process for this concern, and you can't expect any technician to foresee anything.