Freezing during game play and building

appgirl297​  I apologize for the late reply; I've been away from the forums for a few days.

Sims can become corrupt for several reasons, and probably more reasons than we know.  Some are mod-related, and it's possible that a problem would persist through an upload to the Gallery and a download to someone else's game.  Some issues are probably the game itself being less than reliable, for example maybe a buff doesn't get removed when it should have been and is then stuck permanently.  But it's not always possible to find the source of the issue.

If you want to use this content again, I'd suggest testing the sims in a new save, and the build in a different new save with new sims (that you make, not from the Gallery).  If everything looks fine with one, but the other gives you problems, that's reasonably close to conclusive, as in, you can probably safely use whichever one is fine in the new save.  If they're both fine, it's a little harder to know, but you could split the difference and use them together in a new save.

If you want to go back to your main save, just understand that you might see issues going forward, and keep lots of backups.  But the most you have to lose is the save itself and the time you put in; there's no harm in playing forward for as long as you can.