Ok, if we get the ability to choose our avatar's gender, and if the protagonist shown in the trailer is the father. Then if we choose a female avatar, it would stand to reason that the protagonist would be the mother. On the other hand we do not know the gender of the baby, so a male or female protagonist that is the baby would work.
So now we know the protagonist is white. The only way we can allow for a hispanic, asian or black protagonist is to have a character creation screen appear before any of the pre-war scenes that are used for the tutorial, and basically have a separate tutorial for each with appropraite Default White Guy, Default White Gal and Default White Baby being replace by the appropriate Default models. Of course, there doesn't seem to be any opinions on the subject so it would probably be ok to run everyone through the tutorial as Mr. Default White Guy.
As a descendent of Mr. and Mrs. Default White Couple, the apparent race could be almost anything for the protagonist after a couple of generations. But assuming the protagonist could be considered white, there is no guarantee that he/she would look anything like either of the parents depicted outside the vault.