It may be caused by your mods/cc. It would be best with all your save issues to try moving the whole mods folder to another place, delete the localthumbcache.package and then test to see if the issues remain without mods/cc there.
So sorry I forgot to mention, but for my crash/loading issue I did actually try without mods, and it still happened. For the multiple Creature Keepers I will try without mods and let you know!
Sounds like this issue: [COL] NPC roles assigned to multiple Sims (Sometimes duplictes) | EA Forums - 12312826
For the crashing: Is that a specific save ? Could you share some more details on that ?
