2.- Yes, technically you can turn on the pumps, but it is a safety issue similar to not switching on strobos while refueling.
4.- Suppose an V1 engine failure scenery. The main objective is to identify the problem and control the airplane. That could take you to 400 feet. Then asap use the ap if available. That would give you a better disposition to distribute the tasks. It could be a long time from 400 feet to EO acc alt. Even it could be that the EOP interfere with same/other rwy tfc. So IMO the first thing to do the PNF is to activate the EOP on the FMS if it is not already and then proceed with ECAM action while the PF declares the emergency to alert the controllers for possible tfc interferences. There is a recent video where a 757 lost the right engine due to bird ingestion during the rotation. In the video the pilots declare emergency before the acc alt and at the meantime the fire is extinguished. Anyway this is only my point of view. You must check with your SOP.
Tailwinds