I think you're overthinking about the issue of Marie being the middle child, Jenya. From what I've read (and seen pictures), Marie seemed a perfectly normal girl who happened to be behaving expectionally well, thus giving her parents far less reasons to be anxious about Marie than her sisters. And don't forget, in the last few months before the IF's murder, of all four daughters, Alexandra decided to take Marie with her to their last so-called home. She could have taken Olga, being intelligent, or even Tatiana, being the most level-headed of all and the favorite of her mother, but yet she chose Marie, the family's "sweet angel." It should've really given Marie something to be proud of: the fact that during the time of great danger, her mother trusted her enough to have her accompanying Alexandra. Marie was a sweet young woman who only strived to be good and trustworthy; I did not think she had any ambition to outstage her sisters. Marie seemed to be someone who would be content to be standing in the corner and let everybody be a center of attention. Of course, she had all infamous "middle child symptoms" during her lifetime, but all of those symptoms were--and still are--definitely normal for all middle children. She was just a normal middle child who happened to be a Grand Duchess of Russia, born to a family of five children, most of whom had strong personalities. I suppose it's the fact she's a royal made it very easy for observers to examine every and each detail of her life as a middle child.