H4 EAD Extension Application

Hi,

If I apply H1B and H4 extension together. Then only with the receipt notice of H1B (not approved), can I apply for H4 EAD (H1B and H4 still Pending)?

Also, If I apply H4EAD while H1B and H4 is pending, will my application still be processed as filed concurrently (as there is a chance to get approval soon if lucky)? or will it be as standalone application?