I had read some posts about using sims you make into NPC's by putting them on a lot and then evicting them so they were classified as Not In World and thus used as NPC's around town. Sounded great so I just took some NPC's into CAS with the cheat CAS.fulleditmode to make into regular sims for me to play. I changed their Aspirations & Traits and clothing. Saved them and put them into my world. But the problem arose that they still get emotions related to traits I had deleted and changed.
EXAMPLE: NPC has a kleptomaniac trait that I changed to Genius. But she gets the bad moodlet of Tense because she hasn't stolen anything. I have seen this kind of thing happen with 3 different sims I have changed. Sorry if this has been reported before, but be forewarned this will happen if you decide to do what I did. From now on, I will just delete the NPC's and create them from scratch if I want my own creations running around town. And I won't put any NPC's that I have changed into town to play. 
Have you tried making an "Identical Twin" of your creation in CAS using the Genetics feature?
You would end up with the same-looking sim with no residual traits but also without skills or reward traits. Also, you wouldn't need to use cas.fulleditmode.
Save your original sim to your library, then create a sim to move into an empty lot. Load your target sim, make your twin, delete original (if you want), then save twin to library.
Good luck!
