virtually any camera will do for the kn screen, you should pay extra for whatever other features and quality you want out of the camera. The exception might be wanting to photograph text for the screen in which case you need to spend money on a good close up or semi-macro performance.
Most digicams have a basic VGA mode of 640 X 480. These pictures will load directly into the kn to be trimmed, but you would never use them for your normal shots, unless maybe making a web page.
The other factor is memory card, an SD camera will load directly in the kn from the card, but as I explain how to load from any memory card in the book, this is not essential, only convenient.
If money is no object, a minimum 3 megapixel with a minimum of 3 x optical zoom will give great results for most people's non-specialist needs. Digital zoom is a waste of time on less than 3 Mpix and not high on the agenda generally if interested in quality.
I have been most impressed with the quality of canon lenses.