I was very surprised when so many of you asked so many questions about the other four brothers of Count Alexei Orlov after I uploaded the character designs of the musical "Count Orlov":
So I decided to take an evening and create their complete designs to calm down your curiosity and actually show you their designs and explain my reasoning about each one of them.
Twilight Sparkle as Count Gregory Orlov — Gregory was one of Catherine the Great's favorites, and he was the one to achieve to himself and his brothers the title of a count. Since I made Celestia as Catherine the Great I think it would be pretty logical to make Twilight as Gregory, considering he's like the main brother within the entire family and Twilight's admiration for Celestia is on point.
Sunset Shimmer as Count Ivan Orlov — Ivan was the oldest brothers in the Orlov's family, when their father passed away Ivan took the duty of raising his brothers on himself. I picked Sunset Shimmer because she was the earliest Celestia's students, what kinda made her a bit older than Twilight in my mind.
Moondancer as Count Vladimir Orlov — Vladimir was the youngest brother in Orlov's family. He dedicated his life to science and knowledge, and after he finished serving Catherine the Great he became the director of Academy of Sciences. I picked Moondancer because she was all into books and knowledge, not caring pretty much about anything else. She also has a connection with Twilight.
Rarity as Count Fedor Orlov — Fedor Orlov was the most popular of the Orlov brothers at the time, being also the prettiest and the most loved in the circle of the Orlov brothers. I picked Rarity because she cares a lot about how she looks and since Fedor was the most faved and the most popular among all brothers I think he was at least a tiny bit full of himself, just like Rarity sometimes.
The reasoning for Starlight are written under the "Character and designs — Count Orlov musical" artwork mentioned above.
My Little Pony: Friendship is Magic © Hasbro, Lauren Faust