I can tell you with surety, these 4 did not understand right and wrong and were "little children" in every way, but bigger. They had no need of baptism because a person must understand the covenants that are made with the ordinance, and be capable of repentance. In order to do that you have to be free to choose good and evil. One who doesn't understand the difference is not free to choose. The Lord severely chastized the people in the Book of Mormon who were baptizing little children.
We can't talk for them or say we know what's going on in their mind. Really its between them and God. I know that God is loving & just and that everything works out in the end. :0)