1. @poire-z might have some ideas on that front, provided you show some code (because psychic debugging is hard ^^)
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2. IIRC, no. But you can enable swipe gestures to make it less cumbersome in the Links menu (first icon of the top menu).
And it's apparently widely known that the touch input on the KA1 is terrible. But even on devices where it supposedly works decently enough, it's miles behind a Kindle.
3. Probably? ^^
4. PDF only, AFAIK.