The task sounds pretty simple to complete, and I bet I could complete it in less than two days of work. I have years of animation experience in Unity and manipulating models. The only issues I could see myself running into with a project like this is creating new textures or models but it seems like you have those areas covered. As for solving the bugs, that should be pretty quick as well, but all things considered I'd say no more than 3 days to get it polished up for you.