Ellen takes the mike

Interview of Ellen promoting the Petersens' Christmas show

In response to a pointed question, Ellen makes clear that Katie and Emmett are the team that handle the arrangements. Katie is the chief arranger, molding some of Emmett's many suggestions into reality. Mom contributes to some extent because of her expertise in music theory.
Everyone else in the band -- including brother Matt and sister Julianne -- voluntarily takes a back seat in that department.
Previously Matt has strongly asserted that Katie is boss of all arrangements.

But how seriously should we take such light-hearted disclosures? Entertainment news is more about entertaining the public than informing the public.
And what we are told here is not exactly in the same league as Stevie Nicks talking about cheating on her boyfriend with a band member while doing up loads of cocaine.