Immigration case. I arrived here on ESTA from France in October 2020 to visit my boyfriend. I want to get married and not goback

You can indeed seek to get married to BF and not go back to France.

Can I get EAD while our I485 is pending with my wife as a primary applicant? Both of us are in F1 OPT currently.

Yes, you can apply for EAD in the aftermath of having applied for I-485 without EAD.

My husbands mistress is pregnant but she is only working visa?

You will not able to get "deported" or anything close to that.

You could but you will see that it will be futile and waste of time.

Subjects to opt for while doing masters in law? If in future I am planning to become an immigration lawyer

The first year law school subjects will give you a solid understanding of the subjects tested in bar exams nationwide.

That Cronin Memo is still good guidance for DHS.

Is it okay to do freelance work in my hometown while having F1 visa?

This is OK - not any status violation. May get paid.

Can a conditional resident apply for unemployment, and would it affect the process of removing conditions on their residency?

The answer to your first question is "yes", answer to other two is "no."

US Naturalization

Reread the question and see whether is states "failed to file" or "not filed" , then answer with your explanation.

For information purposes - that same fingerprints previously captured were used. Makes no difference now