The remains of all of the family except Alexei and Anastasia have been found. Thus, in my mind, we know the fate of all of the family, with the exception of Alexei and Anastasia.
Where Alexei and Anastasia are, when they died, etc, is open to debate, until their bodies are found and/or more information is available.
I keep an open mind about the fate of these two, but I really don't think it was any "fairy tale" ending. It's improbable that anyone in that cellar survived. Especially not a haemophiliac. I just can't see it happening.