I see that there's a "Change owner" thing but it isn't craftable so I'm wondering if there's a way to untame the wolf/dog/whatever. If that isn't even a feature, please do.

For now, unintuitively, you can right click a dog with the Colar Shear twice to untame him, which will turn him into a untamed dog, not a vanilla.

Hey, thanks for taking the time to create this issue and I'm sorry I didn't get round to resolving it. I've not worked on this project for a while and have decided to archive the git repository. Fear not, there is a fork https://github.com/DashieDev/DoggyTalentsNext which might be of interest. I don't expect to be back within the Minecraft community so farewell and happy mining!