Yes, that would be infringement. Copyright law protects the expressions of ideas. The owner of the copyright to the music you want to use in your commercial would have a valid claim for infringement if you made a "public performance" of his or her music without obtaining the owner's permission. There are exceptions, such as the "fair use" doctrine you mention, but since your purpose is to use somebody else's music to help your business make money, the exceptions would not apply. NOTE:...
The answer likely depends on how, exactly, the dog "ended up with" the father. Assuming the boy had reached the age of majority when he purchased the puppy, the puppy belonged to him the same as any other purchased item would be. (Pets are considered "objects" for ownership purposes; it's not like determining custody rights for a child). If the boy gave the dog to his father as a gift (i.e., intending the transfer to be a gift), then the dog would belong to the father. But if no gift was...
No, that's not a valid case at all. Calling somebody lazy behind their back does not provide grounds for a lawsuit, unless there's more to the story than you provided. (Calling somebody a "lazy Mexican," for example, would be entirely different). You can "discriminate" against lazy people all you want without fear of being sued. In fact, if she broke into your computer, she is the one potentially in trouble. You didn't mention what state you are in, but many states have laws prohibiting...