I'd like have seen the auntie to appear at the end.
For going full circle, while watching the movie, I had expectations about the old aunt being the real mastermind behind the search. She was tracking her nephew for doing justice for his wrong doings when a kid. She knew some how about the house set on fire, and all the fuss about being the heir was just a bait.
On the other side, the Family Plot it reminded me of a typical "Tommy and Tuppence adventure" (Agatha Christie characters). Maybe the ending I was hoping, was too melodramatic and would change the tone of the whole movie. ¡Let's do a remake! ;-)