I picked #4 (run after it, play with it, but not kill it). We've had mice in our garage only once, about 3 years ago (maybe 2 years ago) so only Willow got to experience the mice world. The first time she saw one, she was in my arms, and when she saw it, she started going nuts, kicking me and wacking me, trying to get free so she could run after it. I think once she was on the floor in the garage and a mouse shot out from out of nowhere, ran across to the other end of the garage, and disappeared, and Willow ran right after it.
Judging by my experience of watching them with moths and bugs, I'd say both cats would definitely run after a mouse and definitely catch it, but probably wouldn't kill it. They seem like the types where the size of the mouse (compared to an itty bitty moth) would freak them out, so they either drop the mouse or aren't sure what to do. Once Willow got a bird in her mouth and just froze, but I didn't know she had a bird in her mouth until I'd picked her up and started hugging her, then saw the live bird inches from my face. When I dropped Willow (and shrieked) she dropped the bird, which ended up being okay and was later released out the door (it had flown in through an open window, flown through the house with Willow hot on it's heels, then crashed into the front door which we all heard and investigated)
Judging by my experience of watching them with moths and bugs, I'd say both cats would definitely run after a mouse and definitely catch it, but probably wouldn't kill it. They seem like the types where the size of the mouse (compared to an itty bitty moth) would freak them out, so they either drop the mouse or aren't sure what to do. Once Willow got a bird in her mouth and just froze, but I didn't know she had a bird in her mouth until I'd picked her up and started hugging her, then saw the live bird inches from my face. When I dropped Willow (and shrieked) she dropped the bird, which ended up being okay and was later released out the door (it had flown in through an open window, flown through the house with Willow hot on it's heels, then crashed into the front door which we all heard and investigated)