2. ESSAY,you can develop many original ideas as long as you are working
reference: 1 is from your former employer 2. is from current employer. You have better chance to establish a good impression from current employer. Then ask him/ her for reference.
3. 28 is okay for mba. If you graduate at age of 31--32, you are welcome to IB if you are graduated from GSB which are famous for successful career changers.