Adopted child -- name at Torah and Ketubah etc

Here’s the scenario:

Abraham is the son of Baker, who is a Kohen. Baker gets divorced when Abraham is an infant, and then dies shortly thereafter. Abraham’s mother marries Charlie, who is not a Kohen, and adopts and raises Abraham, who sees Charlie as the only father he’s ever known.

  1. Is Abraham called to the Torah as Abraham ben Baker haKohen, or Abraham ben Charlie haKohen?
  2. On the Ketubah, same question…what name should be used?
  3. On the tombstone (might as well ask it all…)?
  4. When the time comes, does Abraham sit shiva and observe the year of mourning for Charlie? If not, would he be allowed to if he wants to?

Question 1-3
Goes by the name of the birth father. In your example Abraham Ben Baker.

I’ll get back to you on question 4.