What I cannot get my brain around is why, with an engine failure just after lift off, the good engine wasn't at full power (this is not a propeller driven aircraft) until landing profile for whatever runway they could get to was assured.
Why go to full power on the good engine just because of an engine failure? If we imagine for one moment they did the correct thing i.e. raised the gear etc, then there's no requirement to go to full power. If they used an assumed temperature for take-off (and take it as read that they calculated that correctly) then this will allow for adequate performance in the event of an engine failure.
Of course, should you wish, full power is an option but let's not go down the incorrect road of saying engine failure automatically means full power on the good engine. If you're going to go on a low level navex around AMS with your gear down then I would agree that more power would be required than what these guys used but in a 'normal' engine failure scenario we know you can leave the power where it's set for take-off.