Ok, if you are studying for an interview, you are on shaky ground if you have not previously flown the 747. If they ask you stuff that in-depth about an airplane you have not previously flown and you try and pull the wool over their eyes, it will not bode well for you! Furthermore, if you answer the questions correctly and have the misfortune of interviewing with a current 47 guy, he will drive you into the ground. Better study on the conceptual stuff and be honest and say you don't know than try and have a bunch of random facts about an airplane you are not qualified on.
That being said, you should know where fuel is kept in all Cx's airplanes and GENERALLY in what order the fuel is burned, what kind of engines are on each, how much thrust(approximately), and I have heard of people being asked about gross weights. Again though, it is probably better to know APPROXIMATE values rather than exact figures. If you can have a general discussion about CX's airplanes and other heavy jet operations you will come across as a well-read and intelligent individual as opposed to a fact regurgitator.