The person who wrote the newspaper clipping as a warning to Sir Henry
What was the weather the night of the Sir Charles' death?
The reason why Holmes and Watson believed it was Sir Henry who was killed on the moor.
Seldon was wearing Sir Henry's clothing.
Although Watson believed that Holmes was covering another case as he was gathering evidence, Holmes was in fact in this location the whole time.
What does Sherlock ask Watson to due once he returns home from Baskerville Hall?
Report everything back to him.
What are the two reasons why Stapleton pretends Miss Stapleton is his sister?
He wants Laura Lyons to be in love with himself, and he wants Sir Henry to be in love with Miss Stapleton.
The mysterious "L.L." who writes a note to Sir Charles arranging to meet him at his alley the night he dies.
While observing this object, Holmes suddenly realizes Stapleton’s true relationship to the Baskerville family.