Lord of the Flies question

There were probably more than 3 deaths.

Kids never make a headcount in the beginning and after the fire some of them realize the birthmark kid is missing. They are aware of it because of the obvious birthmark in his face and his complaint of the creatures in the forest during the moot makes him memorable to others. So we can assume that it is possible other smaller kids got burnt in the fire along with the birthmark kid as well but older kids do not remember all of their faces.

In the end, when Ralph says there were 2 deaths, it is because either he forgot the birthmark kid or he excluded the death of Simon, since Ralph was in the circle of people who killed him. We can assume most of the kids in that circle will try to forget or deny Simon's death, so they won't be facing the guilt of having committed a murder.

He most likely died in the fire. I think they made it a point to mention that the kid had disappeared after the fire (can't really remember, but I'm pretty sure) so it's probably safe to assume that he burned to death.

The boy with the birthmark most likely died in the fire. When Ralph says that two were killed, he's specifically answering the officer's question about how many were killed. The boy with the birthmark may have died, but he wasn't killed.

I felt like the kids were always in denial about birthmark and no one ever said he died, but everyone was thinking it.
I like Gregory's explanation, but I feel like the only boy who would have come up with a technicality like was that Piggy.