Thanks for bringing up some of these issues to light and it's always helpful to point out these issues to us. We agree that all of those issues you pointed out and we'll be fixing, or at least most of them, in an updated patch after the game jam contest has closed.
The only bug that you mentioned which is particularly tricky in code to fix is the 4th one: possessing both the bat and the ball at the same time. That's because we are using a Raycast2D range around the fox to detect possessable objects, which can lead to possession of 2 objects at once if they're both within range. Hopefully that's something we'll restructure in code in the updated patch. Thanks for playing our game :D