You need to pay $5 or more (before tax) in order to have access to the room with cats. There are around 10 cats in the room and they're all fairly friendly. I use the word "fairly friendly" because some of them will hiss or scratch. When I went fairly early in the morning, I was decently surprised to find all of them except for one awake and very excited and running all around the place. They're less interested by the toys and more amused by your presence and actions. If you pay some more money or donate some, if you can feed snacks to the cats and that definitely gets all of them to you.
In terms of menu options, they have a wide selection of drinks, but only a handful of them are $5 or more and they have some snacks for purchase as well. The time you get to spend in the cat room honestly seems to depend on the line-up at the point in time. On paper they have a 15-20 minute limit, but when they're no wait (e.g. when we went in the morning), we got to spend about 30-40 minutes in there. It's a cool cafe concept with decent drinks, but I probably won't be back that often.