When Marley's ghost visited Scrooge he warned him about the ghosts and his behaviour.
Three were foretold
He told three would visit
Marley told Scrooge that three spirits would visit him: the Ghost of Christmas Past, the Ghost of Christmas Present, and the Ghost of Christmas Yet to Come. These spirits would help Scrooge see the error of his ways and lead him to redemption.
Keep Christmas in his heart for ever more
Because the ghost and Scrooge are nearly seeing visions of the past and the people in those visions could not see them
The Ghost of Christmas Past is accusing Scrooge of wanting to extinguish the light of truth and self-reflection that the ghost represents. By asking to put on his cap, Scrooge is implying that he wants to avoid facing his past and the lessons it holds for him.
Scrooge was never a ghost in the story
The ghost takes Scrooge to the Corn Exchange - Here Scrooge would have been seen on a daily bases in his familiar place. On his visit with the ghost Scrooge hears business men speak of a sudden death and asking what will happen to the deceased properties. The ghost does not get involved in any discussion throughout his visitation to Scrooge
The Ghost warned scrooge to beware of the children. The boy is Ignorance. This girl is Want. Beware them both, and all of their degree, but most of all beware this boy!
This refers to the Ghost of Christmas Yet to Come . Scrooge is unaware of whom the people in the scenes refer to but is starting to guess it might me him and wants the ghost to tell him so
no. Marley is the ghost.