H1 Extention Query, Transfer H1 , IS I-140 Valid?

[h1bee]

Hi,

I have completed by first 3 yrs on H1-b visa with single employer. My visa has been expired on Sept 30, 2008. I filed for the extension with my employer in July 2008. I recently got a RFE query for H1-b extension on March 1st 2009. I have a I -140 Approved with my current Employer in EB-2 Category. Waiting for I-485 to be filled.
Now the question is

If i file for H1-b transfer with different employer as a backup option.

Q1 :- Once the H1-b transfer is approved with different employer, do i have to join the employer immediately or i can wait till i get approval/denial for H1-b extension with the current Employer ?

Q2 :- If i transfer to different company, and my employer is willing to keep the I-140 petition. Will it be possible for me to work for another company for some time and join back my current employer once i get the EAD.

Q3 :- If my h1-b extension is denied before my h1-b transfer approval comes, will i be out of status ?

Q4:- Can i file for H4 visa as dependent to my husband immediately on the same day, when my h1-b extension is denied. Will i be considered out of status @ that time ?

Thanks.

[txh1b]

Read about "bridging" on the forum as your I-94 has already expired. Your transfers are risky at this stage. All underlying bridging petitions have to be approved.

Read the bridging posts and come back with questions if you have any unanswered.

[h1bee]

Thanks txH1b.

I did go through different threads and read about the bridging ... which clarifies my Q3, that i will be out of status if the denial comes before approval. but it did not answer other questions.

If you can explain briefly about it, it would be great.

Q1 :- Once the H1-b transfer is approved with different employer, do i have to join the employer immediately or i can wait till i get approval/denial for H1-b extension with the current Employer ?

Q2 :- If i transfer to different company, and my employer is willing to keep the I-140 petition. Will it be possible for me to work for another company for some time and join back my current employer once i get the EAD.

Q3:- Can i file for H4 visa as dependent to my husband immediately on the same day, when my h1-b extension is denied. Will i be considered out of status @ that time ?

Thanks,