The ancients believed in an afterlife in which one either went to the realm of the gods or simply ceased to exist. However, even by their standards this was too simplistic a view because they believed in more then just one soul. There was a non-personal soul, and certain souls connected to a more spiritual self. We tend to reject the myth as not literal, but some in the religion still do believe it. I for my part do not, and am not sure what to believe about any afterlife, except that I do believe one exists. I think likely reincarnation.
In Kemetic view, yes animals do have souls. However, just like in Buddhism, their personal souls aren't the same as a human's personal soul, and hence no idea of humans or animals reincarnating into one another.
I will try to address your other questions in my next post since this one is getting long ok?