Hi human fly,
take a closer look at your findvoice(), fetchVoiceTable() and fetchKeyTable() methods. Those get triggered multiple times whenever you use the Kit button or the Pad button (in kitSelect() and padSelect() methods).
Also in the Library() where you placed all those functions there are weird dependencies and triggering one of them triggers the other. I just glanced over quickly and did not test any further since I got a project to finish but I think you should start there. Also the way you create tables using the _G metamethods might have something to do with it. Dunno. Just few ideas to think about.
Cheers!