I also had to animate the z's in a second shot, however this was much easier as they didn't have to interact with the puppet.
To get them to blow off of the tree I simply added two position points in After FX and curved the motion line. I then added a high rotation through this path of movement.
 
I have finished shooting in my booth but the animation process is not yet complete! I now need to animate the 'z' leaves that blow off of the tree.

Firstly I cut out Z shapes from book pages and scanned them into my computer and used photoshop to save them as PNG files.
I then imported them into After FX along with the film footage and animated five z's seperately. Once I had the position and timing mapped out I added rotation in aswell, making the z's sway as they blow in on the wind but spin manically when brushed away.