Audrina Number for members include all active members, their children (under 8), and all inactive members, all children of record who haven't been baptised until they reach 110yrs old.
The major growth of the church is coming from members children - active member numbers across the world are approx. 4.5 - 5 million, certainly not the 15 million they like to claim.
As regards baptisms for the dead (and other ordinances) Mormons believe that only Mormons can get into the higher levels of heaven, so everyone needs to be baptised. The rules state that the person must have been dead a year, that if they are recently deceased if there are living descendants, they must give permission for this. This rule is generally not followed.
Think of a famous or infamous person from history who's birthdate and deathdate are known - they've had this done.
So, yes Anne Frank has been 'baptised'. So has Adolf Hitler and the Nazi leadership. Pol Pot, Chairman Mao, Stalin, Lenin - the list goes on.
The unofficial Mormon thinking on this is that the person can reject this in the afterlife, but are relatively uncaring that it's highly disrespectful in this.