With a target message a list can be send to a specific instance. However, since you use the 'note' message, targeting is not necessary. What is important is to free voices using the thispoly~ object inside the midget-granulator.maxpat. Take a look at its help file.
Both the buffer~ and record~ objects have connections to a waveform~ but they don't do anything. If you want to see the content of the buffer there, send it a message 'set dathing' instead.
right that makes a bit more sense, however you lost me with free voices. I checked the help file for thispoly~ but could not see how I can use it to free voices. I noticed the thispoly~ in the subpatch has nothing connected to the outlets, is this the problem?