H1b to F1 VISA - An interesting scenario

[hbmehta]

Hi,

I am currently working in USA on H1b visa; H1b got approved in Oct 2013 through University, i.e. non-profit. Going to India in Dec and my H1b VISA interview date is on December 20.

I have done MS and I would like to do PhD from the same university. I applied for it and hoping to get admission and an I-20 for PhD program (starts in Spring 2014). However, I will not get I-20 in my hands before 15 Dec. (I am going back to the same school and same advisor, so I am sure that I will get admission with funding.)

So, my questions are:

1. My H1b VISA date is 20 Dec. Should I appear for it, get my H1b approved and then apply for F1 from India?
2. Should I wait to get H1b visa approved and then take F1 visa date OR should I get F1 date as soon I get I-20 in my hand?
3. Does it affect if I apply and appear for F1 VISA within 1-2 weeks of H1b approval?
4. If my F1 gets rejected, does my H1b remain intact and can I come back to US on H1b?
5. Any better strategy to deal with my situation.

I appreciate your help. Thank you!