Don't have the book in front of me, but I suspect you're using the ANSWER, not the KEY.

You're very close, but your second one isn't right.

Precise angles are not required.

Lurrud is not needed for the answer, only to attain the answer (as I recall)

If it doesn't work, are you sure you have the right ?

What do you read with your fingers instead of your eyes?

You need to connect the sudoku answers to the keys beneath it. There are hints on that throughout this thread.

If you've solved all the riddles, the 63rd riddle answer (not the key you get, but what you put in to get the key) should give you some hints to the resolution of the storyline.

But there are no definite answers about what happened.