1. Adding specific bit amount redeems is possible but a lot of work hmmmm. Not sure if I'd want to commit to it tbh. But maybe I could add it in a very limited capacity, like 3 options for specific bit amounts to trigger a throw object.
2. Possible, maybe by adding a keyword to their cheer or points that looks for an image of the same filename. hmmm
3. I could add something like that sure. Dodge percentage!
4. This one can already be done, though in a hacky sort of way. Since vtuber kit chooses a throw item at random, you can add 9 copies of the "common" image to the folder, and then 1 "rare" image, so it would effectively have only a 10% chance to show up.