Hi, I got laid off in the month of February and I did a COS from H1B to B2. My B2 Visa expires on September 6th. I have got admission for my second Masters Degree with the I-20 start date as January 2010.

1.) If I apply for a COS from my B2 to F1 visa for my Spring admission, though my B2 expires on September 6th, can I stay here without leaving the country until my classes start in January or would I be definitely needing to leave the country and come back for attending my classes in January?

2.) Since I have changed my status already from H1B to B2, if I again change my status to F1 now, will it later affect my H1B petition approval when I discontinue my studies in-case I get a job?

3.) Which has more chances of approval - B2 extension for 3 more months or COS to F1? Thanks.