@Aichan "At least it was fun while it lasted~😉"
The best way to resolve that is to get a third mistress to have a third son, thus balance of power. If not, get more mistresses and sons, no matter who survives, the best son wins.
IMO, Jakal was waaay to soft with his priorities. The usual policy when there is only one opponent is to simply use a dash of poison rather than go after the less-important mother. You only plot in such a roundabout way when there are more candidates and you can't be seen as to have blood of your brothers on your hand. People like Li Shimin had the right idea, lead an army, murder all other heirs, then tell dad "yo, i'm now your only heir, lolol".