My parents have an I-485 pending. What should they do to be able to travel and come back? Would it affect their application?

did you seek advance parole for them when applying 485? if yes and it's approved they can travel without affecting the 485 process.

no need to change status for taking gre/gmat or any other such examinations

If you obtained your E-2 visa in London, you will not have an I-797 for the E-2. Perhaps, the I-797 being requested is related to the petition...

Can I change my Visa Category

You may be able eligible for a different status. It is not possible to determine the possible options based on the information you have provided....

Visa Officer at the U.S. Consulate ask the candidate to provide the sensitive and confidential documents

The consulate may request these documents. they are relevant to establishing the authenticity of the employer's business and the need for a foreign...

Can I file law suit or a case against my employer.

You need to hire an attorney to evaluate the options.

As my distinguished colleague has suggested you have options. It is not possible to discuss all here, please work with an immigration attorney to...

What can I do with my situation? Can I apply for asylum?

Please consult an immigration attorney who handles asylum applications.

Does this mean I'm approved? If i am, do i still have to wait for the "travel card" ?

It is probably prudent to wait for the papers before you travel.

Potential impact of implementing priority date on EB-1

If you have already filed the I-485, there should be no impact on your case even if the predictions become reality.