L1B to H4 and then H4 to H1B

[Morning Light]

Hello Admin,

I'm on L1B VISA and will complete my 5 years of physical stay in US by June 2013. However, my I94 is valid till August 2013.
My wife is here on H1B VISA which is valid till Sept 2015.
My company will file my H1B visa which I believe will be valid only from Oct 2013.
Hence, for the months July, August & September I'm planning to move to H4 visa so that my wife need not quit her job and she can avoid air travel as she is pregnant.
I have the following questions:

1) Can you please advise whether there is any provision for me to specify my H4 dates, so that I can work till June 2013. Or can I work till June 2013 if I get my H4 earlier ?
2) Is VISA stamping required for me if I do not travel outside in this time frame. ie. for L1B to H4 and from H4 to H1B.
3) Will I know whether my H1B has been approved or rejected before Oct 2013

Thanks in advance for your advise.

[binoca82]

You can request the start date of H4 in the COS application, so that you can work till June.
But, I believe you cannot get a COS to H1, since your L1 expires before Oct 1 (which is the earliest start date of H1) and also when you apply for H1, you will be still on L1 status.
You may consult an immigration attorney to see what are your best options.