It's not essential to disconnect the battery, just don't turn on the ignition or open the drivers door while the pump is disconnected.
As you say bleed off the pressure from the brass nipple, which has to be removed anyway to access the lower right screw.
With the help of a friend you can rock the car onto TDC with it in gear, if it's manual, if not then as you say turn over the bottom pulley.
Not sure how important it is but it is a procedure in the factory manual prior to fitting a pump.