Is there a keyswitch or controller that allows you to switch between poly and mono
Right-click your mouse on the little Poly/Mono slider switch, and select Learn MIDI CC Automation. Then operate whatever controller you want. Kontakt will automate switching back and forth between Poly and Mono depending on the position of the controller.
Not sure what you mean here. IN which instrument? The Melody one or the pattern based one. You can play the notes you want in the Melody one and you can only play patterns in the other one.