I thought her outfit wasn't very appealing but did later read that it was a design by a popular modern designer named Narciso Rodriguez, who is popular with a lot of movie stars. As for the colors of the girls' dresses, I thought they were normal because black and red colors are considered a bit more formal, which is probably fitting for the occasion. I also thought the mother was probably trying to color coordinate with her daughters.
I'm not an expert, but I do believe that, being Black people, they will probably not show up wearing something that Nancy Reagan or Laura Bush would wear. The Obamas are also a fairly young couple.
I guess I am not really seeing Conspiracy here but appreciate your comments nonetheless.