On the subject of child mortality, I thought that there should be some more interesting (but that is not to say more pleasant) pregnancy events. Doomdark has said that there will be twins. In CK1, pregnancy events included: stillborn, stillborn with mother's death, and then all those events where a bastard was born (always male) without knowledge being given of the pregnancy through a variety of events. As to twins, I never found any solid example in medieval and Renaissance Europe for a set of twins of noble birth in which both survived to adulthood. (Though that does not mean that it should not be in the game of course.) Some research should also be done on beliefs regarding multiple births among different classes and cultures. I bring to mind the Biblical story of Esau and Jacob, but twins need not be rivals for the throne; this should as all things depend on traits.
Now, what I was thinking was that there should be miscarriage events (not something some of you may want to model, but it happened of course), which could lead predictably to negative events for both partners, such as temporarily reduced fertility, depression, etc. The other thing, which irked me in CK1, was to have events in which the newborn survives but the mother does not. This seems reasonable. Twins and triplets should also put the mother more at risk for postpartum mortality I would think. Medical knowledge should also play some role in how childbirth is handled. Cordoba was a center of medicinal learning, as was Sicily, so that might matter.
Finally, I want females to have as good of a chance to appear as bastards as males. Biologically, it should be 50/50, of course.