they are all made on the same game "development engine" using fairly standard models with slight customisation.
one of the other creators does put in deliberate easter eggs to her other game, but without a very obvious hint, consider the similarities just to be the coincidence of a shared dev platform.*edit, i just remembered the scene you mean with the two girls in the shop, and yea, its likely an easter egg here too, but i wouldnt call that a rule for all AVNs