I saw your other post in toddler sleep...you might want to prioritize. A new room, ditching the paci, and a new sib too close together might be too much. When I was still pg, our priorities were big boy bed, potty train, and ditch paci. We never made it to getting rid of the paci.
You might want to let him keep it until he's in the new room and back to normal, especially since it sounds like it's a comfort item and might help with the transition.