So I don't know all the answers. I am curious as to whether you have done any exams prior to grade 8 with some of these questions....
Scanning / photocopying pages is fine, as long as you have the original to present to the examiner
Sight reading, no it's nothing from your book, lol otherwise you could just memorise everything? It's a piece of music you will have a minute to look over then try to read, from what I understand, in that time you can use that full minute to try and run through it - playing it on the piano as much as possible and none of it is counted until the minute is up.
skipping notes is not fine. You will be marked down, you are marked on tempo, note accuracy, phrasing e.t.c...
RE Chopin Waltz, if you're asking these sort of questions now, with your exam in 2 days, you're potentially not ready for the exam? Do you not have a teacher?
I'm also under the impression you need to play 3 pieces, although you've only mentioned 2, and worth noting that despite your comments RE the prelude, there was a pretty wide selection of pieces to choose from, what I remember.
I don't know the answer to your aural - test questions. I'm assuming it's going to be you either know the answer or don't, so there is very little need to be sitting thinking for a minute about what you're going to say.