If he's primary petitioner:
In the scenario 1) you use H4, 485 denied, no harm but no income.
2) You use EAD, 485 denied, apply H4 outside US and come back.
If You are primary petitioner:
1) Use EAD, 485 denied, apply H4 outside US, come back to stay.
2) Switch to H4 and stay at home. If 485 denied, still stay at home.