I read your other question, basically they all point to Venus, as you have said Venus was often seen as two stars as it shone at dawn and dusk which were competing with the sun. Lucifer/shining one as a description of a Babylonian King Son of Shahar, is a God in the urgarit text who's father is El a bull god and mother is Asherah. See the Canaanite story of shaher and shalem and avatar attar.
In the Litany of Loreto the Blessed Virgin Mary is invoked as "Stella matutina" (Morning Star), Jesus is also the morning star son of dawn. Is Mary Lucifer/bringer of light/ Eos goddess of the dawn, and her son christ the same as phospherous?
phospherous comes up as a chemical element. I'm not sure what you are referrting to.
When you use the construction Somebody is "something," either the next word or phrase is a predicate or it is a metaphor.
Metaphors are about similarities, not identities. Father's, even those who are not members of royalty, still frequently refer to their daughters as "princesses."
It is also quite probable that Padre Pio was trying to use a limited language to express his understanding of the divine. If so, I would suspect any words he might use would be---by their very nature---both imprecise, inaccurate, and only be able to point in a direction rather than to give gps coordinates.