Mine is doing this exact same thing! I spent so much time on my legacy challenge just for my sims that are married not know each other, they don't know their son, and it says they have zero skills and they're careers are gone! I deleted my mods to see if that was the problem and it isn't! It's just the one save as far as I'm aware! Did you ever get yours fixed or is my favorite save gone forever?
avatheweirdo2 Removing mods can't make disappeared relationships, skills, and careers come back. You can only get them back by regaining them or using cheats to add them back in. There are mods that can help you do that faster - I use UI Cheats Extension for most of this kind of thing, plus cas.fulleditmode. You could also try loading an earlier or backup version of your save.
I don't know of any mod that can cause all these issues. It sounds a lot like you might have a corrupted save.
Note that some career mods are not keeping that particular modded career on Sims if you have Royalty & Legacy. This applies only to the mod's own career, not to any others. See the current Broken and Updated Mods and CC post for more info on that.
I'm splitting you off into Gameplay Issues for more support.
