Tone:
Tone is the feeling the author has when writing the book. So between the many things Misha does not have and the great desperation to survive the ghetto, the author meant for the reader to see that the overall tone of Milkweed would be hopeful.
Mood:
Mood is an emotion that describes the entire storyline this is usually shown through atmosphere, tone, and setting. The mood of this novel would overall be depressive.