when i update my world to the newest version of 1.7.10 MCA and Radiax core, i says there are missing items and every villager vanishes. I installed the mod correctly and my issues keep getting closed so i cant see much help :/

and in the old version children vanished so i dont know what to do

Is there a way i can update and keep all of my family progress, fix the children vanish glitch, and all the villagers wont vanish

You cannot keep any progress when updating from a version of MCA below 5.x.
You must start over.