Page three, that is, the first page of Chapter one
On page 85 of 'The Hobbit' Bilbo asks "What have I got in my pocket?"
Yes, Moria is mentioned in several places in The Hobbit. It was discussed in the planning meeting in Bilbo's smial. It was also used as a battle cry by the dwarves in the Battle of Five Armies.
It depends on the edition you have.
Page 152, Paragraph 3.
ding-dong-a-ling-dang (page 9 )
Tolkien was grading papers one day and encountered a totally blank page in the stack. After a short pause looking at that blank page he wrote the first sentence of "The Hobbit" on it and set the page aside to resume grading. A few days later he began writing the rest of the story.
It could easily have other powers. Some of them are hinted at, but they are discussed in The Lord of the Rings.
That will depend on what version you have. It is used in Chapter 1 and is about page 6 or so when Bilbo complains about the dwarves knowing what he has in has larder.
Read all of instructions page and look at credits
index
Shelob is not mentioned in The Hobbit. Shelob is later explained to have spawned the creatures that lived in Mirkwood. They are the ones that caught the Dwarves and would have eaten them if Bilbo hadn't rescued them.