I love your idea - I did something similar and played it with separate households. So the teen was her own household and I’d play for a while, but occasionally go back to the other household.
I totally get where you’re coming from with the need to micromanage them - in my mind I just liked to imagine them going about their business as usual life without anything particularly outrageous happening while I’m not playing them - unless they bump into ea h other on a lot of course - then I’d act out the drama as appropriate.
Either way I hope you have fun with it!