L1 / H1 to F1 and back to H1

[swayamsarangi]

Hi All,
My situation:

1. I have completed 4 years in the US on L1. Currently I am on L1B extension (I-94 only).
2. I am going back to School this fall and will be changing my status on premium mode so that my status changes to F1 by Aug 1st. By that time I would have completed 4.5 years in the USA.
3. My H1B has been filed in premium mode this year. Assuming I get selected in the lottery and H1B gets approved by May 30 , I will get new I-94 effective Oct 1st.
4. My PERM (labour to start with) is being filed by my company (which does not know that I am leaving the company soon) in May / June this year.

My Questions:

1. Assuming I file my COS from L1 to F1 in July will my PERM filing by my company have any negative impact on my change of status request.
2. If I get the H1B approval by May 30. Will I be able to use the same H1B approval in future and convert from OPT to H1B status once I am done with my OPT period after education or will I have to file a new H1B application after OPT period.

Kindly guide.

Sincere Regards