UPDATE: I've got good news. I did a little experiment by pulling my Document Sims 4 folder and starting my game. Then I returned only my Tray and Mods folders. I grabbed the very oldest copy of my Sim in question, and started him out as a teen. I cheated his skills and fame (via rtf mod) and he was booked for a concert. I set that up and he was unable to perform. However, based on an experiment I did yesterday, I quickly used MCCC to set age to YA and then he was able to perform a concert, in fact all interactions regarding said performance were available. Doesn't, thankfully, appear to be my Sim at all. Yay! Just thought I'd share, in case anyone was interested.
