I'm also having considerable trouble finding information about how these other members of the Imperial family might address one another.
I have tried the usual suspects (Wikipedia and Google-fu with varying phrases including "imperial han family addresses," "ancient chinese imperial family dynamic," "speaking to chinese imperial family," and phrasing things as direct questions to the Google search bar -- because sometimes that actually works) as well as tooling around in the academic databases I have access too (like JSTOR) looking for academic papers that might be able to shed some light on the subject, but have had no real luck.
The characters to be addressed are four daughters of the Emperor (one eldest, two twins in the middle and one young one who is not even in her teens), one son (a "crown prince" if you will), and the Empress Consort herself. If anyone can help me out here or point me in the right direction, I'd be grateful!
