I think a lot of people believe that they have been/could be contacted by deceased loved ones in dreams. I am inclined to think this is possible also. The only time I ever had a dream that made me wonder myself was about one month after my mother died. I had been dreaming of her quite a bit throughout her final illness and immediately after her death, but this dream was different. She came to me, and I could feel her hand (I suppose it was my husband's hand, really, but it seemed to be hers). We were seated in the house she had built, but the house was empty, and we were talking about the afterlife. She was disgruntled, because it wasn't what she had expected. I asked her, "Isn't there a light or something? Aren't there people you would like to see?'' And she said, "No," in a petulant voice, as if she were huffy about being dead. And I said, "Well, Mama, maybe you have to look for it." And she said, "Maybe so," in a completely different tone of voice, as if I had said something to her that she hadn't considered, but was really mulling over. Then the dream ended, I woke up, and I never dreamed of her again, not like that, and not at all for a very long time. It was the last of a sequence of dreams I had had about her during that time.
The thing about this dream that got to me was her tone of voice. It was so Mama, somehow. The disgruntlement, the bemused tone she got when I made my comment. It was exactly, I mean, exactly, like having a conversation with her. And my life with her was one long conversation, anyway.
As for the animal dreams--I have had recurrent dreams about my childhood pet, a dog (also an Irish setter, coincidentally), throughout my life. Every time I have them, I know it is wrong that she should be there, that she is supposed to be dead. But I am always so overjoyed to see her. I do believe, emphatically, that our pets survive in some form, too. It makes no sense to me that a God who had created them would love them less than I do.