What are my legal rights during covid-19 situations?

This is not an immigration question, it is an employer/employee question. I'll re-classify it.

As long as you tell the truth and wait at-least 90 days after signing the I-20 before the I-140 and 485 forms are filed, you'll be fine.

Is international travel to the US from Russia permitted on a valid immigrant visa in current COVID-19 situation?

Since, he has been issued a visa, he can come to the US ll as long as he can find a flight.

Approved I-130?

If you didn't communicate with the NVC at-least once a year ... that I-130 is most likely 'dead'. Go ahead and file form I-824 or a FOIA to see...

You need to talk to an attorney ... from a quick review of your facts, you appear to not be eligible to adjust status to a greencard ... absent...

Please explain how COVID-19 makes it 'no longer financially feasible' to continue your studies. Most schools are using ZOOM .. plus summer break...

Do not use the online form. The CIS computer keeps breaking and losing data. Use a paper form and put 'unemployed'.

Hire an attorney ... IMMEDIATELY ... this can be a BIG prblem.

It might be possible, if your job is secure ... read the instructions closely.

The answers are quite simple and merely require some common sense. (Infact, as Mr. Behar pointed out, you might benefit from a Skype consultation...