In real life or in the world of drama, most people have run across an archetype: a woman who has buried two husbands and is now married to her third husband. She prefaces most topics with, "Well, as my first husband used to say..."
How her third husband resists strangling her, we never learn.
I thought about that when I adopted my second (and current) dog. At first I wanted another miniature poodle, as my first dog was. But what if I started comparing the second miniature poodle with a nostalgic and romanticized view of the first miniature poodle? Number 2 would always suffer by comparison. Unfair. It would ruin what would otherwise have been a good experience.
Thus I chose a second dog who was opposite of the first dog in several ways, and was glad that I did.
How could that logic be applied to Number 3? My best guess is to choose a dog that is different that the first two. Let her shine in her own limelight.