I would recommend you discuss these questions with your company's attorney and/or other experienced immigration counsel before moving forward.
That being said, you need to submit the L1A Petition before the expiration of the L1B, and there would usually be no 6 month prior requirement.
On another note I would advise you against applying for both the L1A conversion and L1B extension concurrently. However, if you apply for the L1A and it gets denied but your L1B is not at that time yet expired, you should then be able to apply for an L1B extension. For these reasons your employer might give some consideration to submitting the L1A through premium processing to ensure a very timely answer.
Options depend on facts. You really need to meet one on one with an experienced immigration attorney, whether myself or one of my colleagues, so that he/she can review all your documents and facts in order to determine what your options are.
J Charles Ferrari Eng & Nishimura 213.622.2255 The statement above is general in nature and does not constitute legal advice, as not all the facts are known. You should retain an attorney to review all the facts specific to your case in order to receive advise specific to your case. The statement above does not create an attorney/client relationship. Answers on Avvo can only be general ones, as specific answers would require knowledge of all the facts. As such, they may or may not apply to the question.
I agree with my colleagues.
PROFESSOR OF IMMIGRATION LAW for over 10 years -- This blog posting is offered for informational purposes only. It does not constitute an attorney-client relationship.