Heres always been my problem with the whole purgatory idea.
If you are with the people that matter most to you, after awhile you sort of get too many degrees of seperation.
Heres what I mean. Claire and Charlie are important to one another, so they are together. They also both care about Aron, so he is there.
But Aron had his own life. Odds are his ideal form for all eternity isnt a baby. What about all the people in his life that made a difference for him? His eventual wife and children? And his children would feel the same way, and want thier family and freinds there. Eventually it becomes an infinite amount of people through various connections.
And if you say that Aron is only a baby becuase it is ideal for Claire and Charlie that he is a baby, then that means Aron isnt there at all. If only the people you care about are in your afterlife, either the only people you know are eachother, or you arent really with them.