Hmm, well I was trying this. I played with the pre-made households leaving the randomly generated ones unplayed. Then, I have my auto-aging settings as auto-age (played sims): Only Active Household, and Auto-age (unplayed sims): yes. Hopefully, the pre-made families like Goth, and Pancakes won't age, but the randomly generated ones would. I'll update to see if it works.