It is difficult to give an answer based on the information you have provided. Maybe it is best to consult an attorney now to help you through this...

How would I know if my immigration case has been transfer to a different service center?

They can switch the processing facility at times. It doesn't usually mean there is any problem with your case.

How to apply for a visitor visa???????

You can go online to embassy website to request a visa and interview time. But it may not be granted since your children are in the US. It would be...

I was denied for the DACA. I want to know if can reapply?

You can reply if you get the documentation you needed. If you want to confirm whether you are likely to get approved, hire an immigration attorney...

Could I be eligible for a L1B visa with an immigrant (family) visa petition pending?

Yes you can do both but it might not be worth doing the L1 if you are at the consular processing phase.

Is it possible to file for unemployment with deferred action (DACA)

This question is related more towards employment law then immigration. If you were an employee then you may be entitled to unemployment benefits....

I'm applying for E2 status but my husband is here on visa-exempt status, so do I just notify consulate abroad once I'm approved?

After you are approved he can set a consular appointment and take the necessary documents with him to get his visa. Your attorney should be able to...

I am under F2 visa, may I get stock option and equity from another company? I'm in California.

It depends on if it is a gift or payment in exchange of labor...

Do company sack employee for past expunged convictions ?

If the attorney is the employers attorney, then the confidential relationship is probably between them.

H1b pending for 1yr because of security clearance. Can I contact dhs or FBI to find out why?

You can contact them but they won't give you an answer.