I had an idea while studying yours though.
What if the cats who can currently see the mouse got points, increasing every consecutive second (up to a cap, to make it not too profitable to plainly follow the mouse), while the other ones would rack up MP, based on how far they are and to help them catch up? When the bar is full, they would get an item (like you said).
Obviously, when no cat sees the mouse, no points nor MP are awarded).
The cats would have to choose between chasing the mouse head on, or waiting and striking at the right moment.
The AI controlled cats (when there's less than 3 cat players) would obviously follow the mouse blindly (to put pressure on the player)
Meanwhile, the mouse could receive MP for every second it is hidden, and when its meter is full, an additionnal power pellet could appear for him to use.
Do you guys think that's a good idea?
Edit: (oops, I really misinterpreted what you said )
So, what if you rewarded cats for being closer to the mouse, but didn’t reward them at all when the mouse was in their sights? You could give them a little detector that tells him if he’s “Cold”, “Luke”, “Warm” or “HOT”. The closer you get to mouse; the quicker you gain MP. That way, your giving cats a boost when they struggle to close distances on the mouse, without giving them an advantage when they shouldn’t have/need it.