H1-B to H4 or F1 change for status

My wife is a student but got her H1-B this year. Now her status got changed to H1-B and due to pandemic her job is at risk. Can she move back to F1?

I have my i-140 approved, how soon can we get h4-EAD?

She can file H4 or F1 change of status if she is eligible.