KittyTac is WRONG for vanilla DF (sorry, I don't want to attack KittyTac personally, just warn against incorrect advice).
Animal people are less usable than trolls as captives (those can be used as cannon fodder and in building destroyer roles through careful release).
If I understand it correctly, modding animal people to get the exotic pet tag cause them to behave like gremlins, i.e. petition for citizenship after a year (skipping residency: the cage took care of that...).
Gremlins have to be retrained regularly even after becoming citizens, which is a pain as they tend not to show up for retraining, so I use DFHack to change them to Tame when becoming citizens. Also, DF doesn't allow you to assign professions to gremlins (hauling is enabled by default, and cannot be changed from within DF), and you can't see their thoughts (which is a pain if you get demands from a noble, but can't see what those demands are). Dwarf Therapist allows you to set and change professions, however (while Dwarf Manipulator does not).
As far as I understand, all of the above would apply to forcibly recruited animal people with the exotic pet tag (probably excluding the cavern animal peoples, as those are enemies of your civ).