回复：急：老板不写J-1 Waiver 的Support Lett

1. Yes. You can mention your boss will sponser your H1b in your statement. That what I did without any trouble.
2. Yes. If you have I-20.
3. Nobody has ever asked for boss's sponser letter. Just some people thought that might be help. In my opinion, don't send anything that is not requested. That will not help, only make your case more complicated.
3.? (Suppost to be 4.) Must get waiver before you changing visa. I knew some people changed to H1b without waiver, that might be caused by oversight. But probably will have trouble in future.