Is it possible to file COS from H4 to L1B using form I-539?

NO, this will not be a COS case. The employer must file form I-129 .... then, when approved you will have to file form DS-160 with the US Consulate.

Can i my employer file H1B non cap visa with USCIS now?? is USCIS Accepts H1B non cap applications outside USA?

The application will not be 'yours' H-1B petitions are the property of the prospective employer. NO, cap subject petitions can not be filed at...

Do we need to be in valid L1 status until my COS approved or I can apply cos just before my L1 expires?

First, because at-least 4 times more H-1B applications are received than visas are issued ... unless this is an exempt employer, you should develop...

Go ahead and call CIS. Normally they send a letter with an important bar code.

Can my girlfriend move out of her current au pair program for a tourist visa and legally marry me?

It is very difficult to change from a J-1 to B-2. Why not get married now?

What happens if I leave the country before a decision is made on my I-539 is made?

First of all, are you sure you're on a B-1 and not a B-2? Write a certified letter and include a copy of your plane ticket.

Yes, even with zero income, you are still the primary sponsor ... and will remain 'on the hook' for 10 years.

How long does USCIS(California service center) take to withdraw h1-b?

Keep in mind that it is not "your" petition, it is the property of the employer. Did you type the year correct 2020, or did you mean 2021.

Q: I was wondering if this delay is related to relocation? A: Yes absolutely ... it is never a good idea to move. Q: What options do I have to...

Sorry, there is no automatic extension for the DACA C33 category. Maybe your employer will give you an unpaid leave of absence.