H4 after I-140 approval Retain status

[Srinjoy Nath]

I am in H1B VISA status, my PERM has been approved through my current employer in August 2016. Due to my baby born I am planning to be in H4 for now since my Husband is in H1B status.
Can i get i140 approved and get into my husband dependent H4 status and then again in December can i activate my H1B, get into same employer's i-140 status and apply for GC next step 485.
Meanwhile if my i140 gets approved can we both apply for EAD since my husband will be covered under my PERM and i-140.