It says on the part to remove the camshafts install 5.0mm pin punches to the no.1 camshaft holder. Are these pin punches truley necessary?

 

No. They just keep the cam from spinning when you break the pully bolt free.

 

You don't need to use the pin punches or remove the crank pulley to remove the head. All you need to do is loosen the timing belt tensioner enough so that you can slip the belt off of the cam gears and totally loosen up all of the cam caps (I would follow the order they give you in the books). Then when everything is loose and ready, just rotate the cam slowly at the cam gear with you hand a little and all of the cam caps will pop up when they get pushed from the cam lobe pushing up on the rocker arms.
It's that easy and you don't have to use those punches to keep the cams straight or remove the timing belt, just make sure you line everything back up to tdc again before you turn the key.