Foreigner bringing in more than $10,000?

I agree with the previous answer. You just have to complete this form - "Report of International Transportation of Currency and Monetary...

How can I change my status from F1 to H4?

Yes, you can by filing Form I-539 Application to Change Status.

Can I travel during N400 process ?

Yes you can travel. However, it is advisable to consult with an immigration attorney prior to travel to exclude any potential inadmissibility issues.

What should I do?

You should hire an experienced immigration attorney to represent you and your family.

I-765 status never changed to "Card being produced"

If your inquiry is about a delay, it's best to call the USCIS customer service number. Please note that the online status is not always promptly...

Why USCIS website shows same processing time for I-130 for immediate and non-immediate relative @ Nebraska Service center?

Unfortunately, the posted processing times are "estimates" and "objectives" and not always reality.

Need to know if an Immediate Family Green Card filing in USA is legal if I travel on B1/B2 visa ?

I agree with the previous answers. Not a good idea. if you are currently in the US and will like to AOS, then apply for AOS and advance parole...

How I can convince the US consulate officer that wife my can get her H4 visa based on my approved H1B petition ?

More information is needed. Do you have H1B status? If so, talk to your employer's attorney about how to acquire status for your wife.

Yes, you need to apply for an EAD based on your current valid E-3 status. The L2 EAD is no longer valid.

10 years Green card?

If you are still married to your current USC spouse, You can apply for naturalization 2 years and 9 months after your green card issuance date.