It is better to seek the advice your your lawyer in this case.

1. If your H1 was approved without I-94, you have to go out of country and re-enter for a new I-94 at the port of entry. If you still have job and recent paystubs, you will get the new I-94.

In order to transfer H1 to other compnay you need to have an unexpired I-94.

2. You can go to F1 if you file your change of status into F1 while your H1 is still in-status.

3. is same as 2 (joining to Kaplan is changing status to F1)

I am not clear about your current situation, your extension was denied... Are you still working for the same employer? Why was your extension denied? These answers need to be clarified to get better answers.

Anyways, Good Luck prch