Click on the vertical gray bar to the right of the Closed Hi-hat and it selects the entire row of notes; press CMD- or CTRL-c to copy the Closed Hi-hat row.
Go to the song part you want the copied row of Closed Hi-hats, press the gray bar next to Closed Hi-hat and press CMD- or CTRL-v to paste.
You can use the same selection method to delete an entire row of notes or change their velocities.
Your second question is answered in your other post.