It's such a pity that Ruyi and Hailan invested so much in the fifth prince but lost to Consort Ling....I wonder what type of Empress Dowager, Hailan would have become, had the fifth prince lived and became Emperor
I suspect she would have become as powerful if not more so as her predecessor. She had become quite formidable by the end of the series. I suspect she would have been more involved with the harem than her predecessor. I don't think there would have been much that happened that she would not already know about. She definitely would have had a hand in training her daughter in law for the role of empress.
I think this was a calculated risk by Yongqi. He would have guessed that it could go either way with the Emperor and this way he’d at least have the Dowager’s support!