I just can’t agree with these largely unsubstantiated assumptions. There’s nothing thoughtful or reflective about that most powerful love that we experience, “mother love”, it’s largely the product of reward chemical cascades in the brain. Haven’t yet read your cites but I strongly suspect that very similar if not identical brain architecture and reward chemical loops exist in the doggy brain, and that like those in the human brain they can be redirected to and co-opted for other relationships.

In all likelihood our concepts of romantic love actually describe this sort of cooptation with the emotional bonds of motherhood, mutually connecting mother and offspring, sustaining and reattaching in adulthood to promote pair bonding and its benefits in raising highly intelligent offspring with long periods of intellectual/emotional development.

We see many pair bonded animals in higher intelligence species, I think there’s much to do to distinguish our experience of love from the parrot’s, or the dog’s.