Can I fill out Form I-485 together with Form I-130 for my brother who is legally within the US?

No, that is not possible for multiple reasons.

Is it risky to enter United States with pending green card application?

The risk is that the ESTA registration could be denied. You must not be seeking to enter the US permanently as a visa waiver applicant.

Presently, there is a not an office offering swearing-in the same day as the interview.

Working without authorization would not result in automatic rejection or denial of an asylum application.

Can I apply for the US citizenship?

You may be approved for Naturalization as long as you are no longer on probation and you otherwise meet all the requirements. Consult with an...

Denial H1B extension supervisor review Timeline

You need to consult with an immigration attorney once you have the written decision denying your H-1B extension.

An F-2 dependent may also apply for work authorization as a derivative asylum applicant.

It would most likely raise an inquiry into fraud in the asylum application.

Is there anyway to get a green card now?

Consult with an attorney. many questions would need to be asked and answered before one could properly advise you.

Can my sister apply for my green card under f4? I am a Pakistani national married 42 years old.

Yes, your sister may file a F-4th preference petition on your behalf at any time. Note that there is a significant wait for visa availability...