There are basically no reasons to chose Zhenya over Sonya THIS SEASON.
Samodurova outskated Medvedeva pretty much most of the season. Sending someone because the person did well one / two / 10 years ago is wrong. As someone said on another forum, "what you get for your past achievements is a pension. you get medals for skating well right here right now". It may sound a bit brutal, but this is how sport works, or at least should work.
At nationals, Sonya also beat Zhenya, and if scoring was fair, she would have also beaten Alina, and her margin over Zhenya would be much higher (to start with, subtract those lv4 rotations in SP, which are not even a matter of personal oppinion).
Same goes for Stanislava. She outskated Zhenya at nationals (we can discuss scoring, again, but clearly she skated better). During the season, both skated on same level.
If Zhenya is chosen over any of those 2 girls, it will be highly unfair.