It is worth further exploration!
I have explored this before and had to be very meticulous making sure everything was in a know state and a lot of deleting files and restarting Processing and sketch.
At one point I simply lost track and was both optimistic but also uncertain about outcomes.
Have not revisited this until now… and will be sure to document and be able to reproduce before posting anything formal.
Proceed with caution. 
It does not seem to work with this one:
JavaFX Controls Preview
All jar files copied to library folder as per:
No jar files in the sketch folder.
Error:
Cannot find a class or type named “Tooltip”
I copied these three to the sketch and it worked:
Output:
:)