When I'm bored, I make lists of animals at zoos on iNaturalist. I have a list for the Bronx Zoo which I definitely know is incomplete. I'm going to post the link to the list so everyone can view it and then let me know what is missing. Bronx Zoo Animals
Technically yes but you can post captive animals, you just have to specify that they are captive. These lists are also to help me keep track of animals that I've seen or are at a zoo that I haven't seen.
I like your idea. However, I think the list is not 100% accurate/correct. Since when does Bronx has Cervus hanglu? Bronx Zoo Animals
Generally yes but captive animals aren't disallowed. The lists feature (which is used here) can be used for anything a user wants.
If so (and if the new taxonomy is valid, saying that the Bactrian Deer is a subspecies of Cervus hanglu and no longer regarded as Cervus elaphus bactrianus), then you are right and I was wrong...