I heard back from the pet hospital.
(1) Chako will be released from the hospital on Saturday. I will go over there at 3pm to get her.
(2) They are doing a special “stray cat rate” for her. Everything (operation, health check, week’s stay at the hospital) will be 21,000 yen ($262). I will split the cost with my neighbor (I hope). Unfortunately we can’t use the small subsidy from the hokenjo because the hospital is in a different ward.
(3) The cause of Chako’s missing paw was an accident at some point in her past. The vet said it doesn’t hurt.
(4) The vet’s best guess at her age is about 5 years old.
I will have to get her and just release her near my house. I’m sorry to have to do it that way since it has gotten cold and is rainy now, but nobody wants to take her so there is no choice. If anybody wants her they have until Saturday to let me know!