I think I only delete Baby Ariel, and that's because she's not a Maxis OC but a real life celeb.
Alex Moyer, Jasmine Holiday etc get made mortal via MCCC (only legendary sims like Father Winter and Grim should be immortal, not regular ones).
I like to move in the homeless premades and sims from the base game trailers at the start of a rotation (except for special sims like ole Crumplebutt and Father Winter), and I introduce newer Maxis trailer/Gallery sims gradually over time.
All premades get hair and make up tweaks to suit their face and hot/cold weather outfits added. I like to carry their everyday style over to the hot/cold outfits though, so for example, Eliza might wear the same top and flip-flops for hot weather, but would have jean shorts instead of jeans. This way they keep their iconic look and I can spot them around town. Additional outfits they have to acquire through gameplay.
