I think any survivor could have fit the propaganda role as "orphaned boy/girl emperor/empress seeks to reclaim homeland from red terrorists". It sure does suck that their father chose to elevate them to the status of blood successors. It sucks that his choice for an undemocratic regime fueled by violence, which couldn't even provide basic survival for the people it spared, knowingly endangered his children because the stability of the state was tied to their survival rather than the survival of its citizens. It sucks he decided to create several million orphans in the pointless aristocratic war that preceded the revolution that was a consequence of his barbarism.