I think baby-like facial features are just a part of the domestication syndrome. There has been this long-going domestication experiment with silver foxes that could show that when only selected for tameness the foxes still expressed most of the traits found in other domesticated animals, too.

Belyaev was correct that selection on tameness alone leads to the emergence of traits in the domestication syndrome. In less than a decade, some of the domesticated foxes had floppy ears and curly tails (Fig. 2).

Over the course of the experiment, researchers also found the domesticated foxes displayed mottled “mutt-like” fur patterns, and they had more juvenilized facial features (shorter, rounder, more dog-like snouts) and body shapes (chunkier, rather than gracile limbs) (Fig. 3).