Unfortunately, enotes regulations only permits you one question - you asked several in your question, and so I have had to edit it down. This excellent poem personifies death in quite a startling way in the first stanza. Note how Dickinson describes him:
Because I could not stop for Death -
He kindly stopped for me -
The Carriage held but just Ourselves -
Death is therefore throughout this poem personified as a kind, elderly man in a carriage, who stops for his passengers, picking up when there time comes and taking them on into the next stage of life. Death is normally personified as something terrifying, scary or horrible, and so personifying him in this way immediately makes us think about what Dickinson is trying to say about death and her attitude towards it in this poem.