I will take a stab at the check-ride failure question. First off, you should be able to explain the circumstances for each one without being defensive. Also the learning experience from that event. Airlines look closer at 121/135 checkride failures as opposed to those during initial flight training. I would venture to say there is no set number that would knock you out, however if you have a history of them in the airline world then it will be an uphill battle. But for sure, if you can't talk about them or you try to blame someone else for the outcome you will not be favorably considered. Best of luck.