I have a theory: A GAME THEORY

So hear me out:

Because Gf is from the Dearest family and that she is called 'Lucy' by her family members, Gf's real name is Lucy Dearest.

In a somewhat similar way, because Bf is from the Fairest family and he is called 'Keith' by his family members, Bf's real name is Keith Fairest.

Therefore: the real names of Bf & Gf are Keith Fairest and Lucy Dearest.

Are you talking about FNF?

Yes.