DaNiX_2906 I just wanted to note that I've tested your save (with no mods or custom content present) and it crashed for me too when exiting CAS. Then I moved the household to a different lot, the one at the bottom of the Henford map, and got another crash when exiting CAS. I don't have time to do mor than that at the moment but will come back to it if no one else comes up with other ideas.
If you want to experiment yourself in the interim, the next thing I'd try would be to install ShowSimInfo (the one from frankk is current; the one hosted by Mod the Sims is not) and see what traits the sims have, and whether removing any extra or hidden traits helps.