Thanks for the chapter!
Isn't Go the Chinese equivalent of Reversi and Shogi the equivalent of Chess? In any case, reason why keeping her at the palace quietly is to allow her to recover in peace while fanning the flames of the Feng family's misfortune when she returns.
As for name and title of first daughter I think he's talking about restoring her position in the Feng family as even if he approved of her as the 9th prince's wife it'd be as the 9th wife in reference to her husband's position and wouldn't be recognized by the people until a marriage ceremony had been done. Considering the 9th prince inherited his personality he's probably got something clever planned that's part official and part being the Emperor declaring is so with any objections punishable by death.