H1B(221g), started transfer to new company, embassy approved 221(g) !!! Is it valid?

Hi,

Went for stamping in Jan-14, and was issued 221(g). Its been 4 months and no reply from Embassy. So we decided to transfer H1B to new company and go for visa stamping interview on newly approved CAP Exempt visa. New company started the transfer process in Apr-14, I did not yet hear from them whether LCA is transferred or not and CAP Exempt processed or not. 

Surprisingly, I got a call from Embassy to submit my Passport for stamping. Kindly help my questions ?

Will the stamping be valid when I submit passport ? 
Should I get the transfer cancelled with New Company ASAP? Can this be revoked ?
What if the existing LCA was transferred to new company already ? Then the basic petition itself would become void? 
Can I still work with Company A, which processed my visa earlier ? 
Is it suggested to inform Embassy to consider new LCA transfer and CAP Exempt visa instead of old one. (Note: As far as I know new company just started the LCA transfer, approval would be still pending by authorities, so I dont have any concrete info to tell Embassy)

Please put your thoughts ...

Regards
Amar