halacha - Do the Gentiles have "Three partners in man" and why they exempt from honoring parents?

The Gemmorah in Kiddushin 30b states (:

"שלשה שותפין הן באדם הקב"ה ואביו ואמו"

There are three partners in the forming of a person: The Holy One, Blessed be He, who provides the soul, and his father and his mother.

Mishna in B"M 2,11 also explains it to be the reason for honoring them, as they bring the person to this world.

"אבידת אביו ואבידת רבו - אבידת רבו קודמת שאביו מביאו לחיי העוה"ז ורבו מביאו לחיי העוה"ב "
..." because his father brought him into this world, but his teacher, who taught him wisdom, brings him to live in the world to come;

I was wondering:

1. 
   

   Are the same 3 partners participating in Gentiles?

   
   



2. 
   

   If yes, why the Gentiles aren't [explicitly] commanded on honoring parents?

   
   


3. 
   

   Also, Rambam and Shu"A (רמ"א) rule that a convert has no obligation of honoring his (gentile) parents, despite the fact that they did bring him to this world (not the spiritual one)?.