The main conflict is that Harry is now old enough to face voldemort for the first time. however harry does not know this so he assumes that this fight will be between him and snake but it will actually be between him and quirrel.
5 is opinion so you can basically say whatever you want
I believe number one is false and number two True
It is a metaphor representing not just the 'mask' of the plague, but also the 'masquerade' of the ball and the 'masquerade' of pretending to escape death.
I think its <span>dark and dim. </span>