The answer is: had transformed
Leaves dancing is the personification
It would give an image of light floating leaves twisting and twirling in the breeze. Kind of like actual dancers on a stage. I think of more ballet- people dressed up in yellow, orange, red costumes. If you think of how they move, kind of "floating", you might could say. Definitely very active.
Do you have a question or did you just want to get that off of your mind?
He questions the tradition of wall-mending.
They are considered themes because they appear frequently in literature.
