They've stated they intend all companions to be origins/tadpoled. And yes, more are coming. From what I understand, the current 5 aren't any more "main" than the ones to come.
From the March reddit AMA:
Will all possible companions be available as Origin character options or will there be companions available only as NPCs?
Swen: We are trying to make all characters with backstory available as origin characters. Other than that, you will be able to recruit generic mercenaries and customize these. We’re also planning to allow you to build a custom party from the character creation screen though that most likely won’t be present in early access from the get go.
La mejor noticia !!!!!!! D; pasa link donde leiste eso mi tio google no me muestra mas que cuando iba salir Baldurgate 3 -.- 2h para encontrar algo ni idea por que no entiende
