I would go and get that baby tonight. Leave a note on the door where she is. Sure it is tresspassing, but tresspassing is less offensive than animal neglect. Plus, you already have your statements to AC and the other neighbor to back you up. If the daughter really does come by, then she will know where to look. If the daughter doesn't come by (or doesn't bother coming to your door), then you will have proof that the dog has been abandoned and you can call animal control in the morning. I am sure the poor little baby would rather sleep in your garage then out in the cold.
P.S. I know that historically two females can fight. I however had two females under one roof for several years. Just because they are female doesn't mean they will fight.