Can I apply for I-485 before I-140 is approved? Or should I file I-140 in Premium processing? How long is medical exam valid for

You should be asking your employer's attorney these questions.

N/a

Once the EAD is approved she can work anywhere or nowhere. She can also study if he wants.

You have to file the application based on where you live.

Can I apply with my cousin for asylum or do we have to apply separately?

You cannot include your cousin on your application for asylum. Each person should file their own asylum application.

Can she travel to canada or Mexico to change the status from H1B to H4? Or travel should be on the home country?

Travel should be to the home country to change status unless it can be done in the US. Check with the attorney handling the paperwork.

Work whatever jobs you can get in your fields of study.

What is visa bulletin current date for F2A category?

Use table A to find the current priority dates.

It does not matter if you provide the I-20. You must provide proof of a legal entry to the United States with the application. Use the stamp in...

Well use the USCIS website and the fillable forms they provide. Just type regular. Capitalize proper words but use small letters for the rest.

Who decides what jobs fulfill my OPT requirements?

Listen to your designated school official - she has the experience working with USCIS regarding these matters. USCIS is the agency that will...