1. Yes- except for US university transcripts/ diploma which you will get as a  sealed one from your registrar's office of your school.

2. It depends- if you know someone at HR pretty well or if you have a great Supervisor who can keep confidentiality that will be fantastic. But that is not always the case. You can ask them you need a experience letter for someother cause, like persuing for Masters or PhD program that you need  such letter (as in whom it may concern letter that only mentions your job experience without saying what the letter is for).  I would NOT tell my current employer about intention of moving to Canada or elsewhere at this early stage. They might find your substitute right away and make your work life a living hell.