Can h1b/H4 extension(prenium processing ) be filed parallel to H4 to F1 change of status filling

[ricx]

Myself H1b and wife's H4 visa/I-94  expire on May/1st/2014. I’m applying for H1 and H4 extension together in premium processing by March/20/2014

Spouse is currently enrolled in school on h4 status, going to complete her  studies by dec/2014
Later on  my spouse is going to apply for H4 to F1 change of status on April/1st/2014  , for Fall semester Aug/25/2014(Fall semester) and I -20 date is Aug/2014.

 

On May/02/2014 what will be my spouse status h4 or f1 ?, if both h4 extension and h4 to f1 cos get approved

On Aug/25/2014 what will be my spouse status h4 or f1 ? , if both h4 extension and h4 to f1 cos get approved

 

Do I need to wait for h1b/h4 extension approval before applying for spouse h4 to f1 change of status?

 

What should be best to do , so that she can f1 status by aug/2014...