New H1b pending, opt expiring and new h4/ead pending

3 yrs Opt expires on dec 31st(no more extension). However filed change off status from f1. Now it’s dec last week but Awaiting on “new” H1b approval after submitting RFE response. Also filed H4/EAD starting Jan 1st before opt expired so that won’t go out of status. Now H1b, h4/ead are all pending. Couple of questions

  1. I believe cannot work after dec 31st if h1b or h4 ead is not approved by then?

  2. what happens if H1b is approved first then they process h4/ead or Vice versa?