I need to pay my fine for my visa?

There is no fine. If your I-94 has expired, you need to leave or incur unlawful presence.

H1B transfer do i need to file 539 for H4 as well having valid I-94 from previous employer ?

Dependents do not apply for a new H-4 each time the H-1B family member changes employers. But they do need to keep their H-4 valid by filing for...

F1 to EB3 based on employer sponsorship. Is it good option?

If you intended to enter the US as an F-1 nonimmigrant, your F-1 remains valid so you do not have to leave the US during the I-140 adjudication...

For how many days can I stay legally in the US after my CAP EXEMPT employer terminates my employment? I am on a H1-B CAP EXEMPT

Taking 30 days to wind up her affairs in the US should be fine since up to 60 days is allowed at the end of H-1B employment.

Answered already. It is asking for first time you entered the US as an "immigrant" so as a green card holder.

It is asking for when you first entered the US as an immigrant (green card holder) and where.

How much is the fee for the ds-260?

Go to the Embassy website and it will tell you the amount and advise how to pay and get a receipt.

The NRC is the central repository of personnel related records for military and civil positions in the US government. In 2018 it assumed...

When?

Hopefully you have a receipt proving the affidavit of support was received. You will just have to wait; timing is unpredictable due to USCIS...

If you're traveling outside USA and your H4 EAD/AP gets approved, can your spouse{who is in USA} legally mail those to you?

Yes, they can be mailed outside the US.