Idea #1: When I first got Get Famous, I made a family of two young adults. It was a brother and sister household living in the rundown neighborhood in Del Sol Valley. The backstory/plot was that they grew up in an orphanage. Their parents died and they along with their baby sister were sent to an orphanage. Ther brother is older and is very protective of his sisters and wants to give them a great life. He left the orphanage as a teenager and took on a lot of odd jobs an part-time jobs to make enough money to afford a small trailer like space (made with get famous props and the cheapest appliances and furniture). His sister left the orphanage a few years later after high school and has always dreamed to be a world famous celebrity, specifically an actress. She's self-absorbed but not in a bad way. More like, she's pampered and spoiled because of her brother.You could start the save here and have the brother do a freelancer career, or a part-time career, and sign the sister to and agency.
I started my game here and a bit down the line, when they had a better house they brought the younger sister in while she was still a teen. In my game, the brother ironically became super famous way before his sister because he was painting a lot for money, and selling paintings gives you fame. He was also mixing music and busking for money so he got a lot of constant fame. He used his fame to talk up his sister and make her more famous. I ended up making the youngest sister very down-to-earth. She really did not like the spotlight and watched as her siblings morphed under the public eye. She ends up befriending a girl in high school whose family owns a huge farm, and spends most of her time with that family trying to feel as though she has a normal life.
Another interesting point, I spent almost all the money they made on creating a huge house with a decked out pool area but with almost no furnishings. I would always spend their money to get the Get Famous furniture. They were/are rather house rich/cash poor really adding to their story. The oldest brother fell for Venessa Jeong (who was his sister's best friend) but they've been through a lot and he has seriously changed (becoming a famous painter).
Idea #2: I don't know what packs you have but I think it would be cool to have a family or perhaps one sim that has one of the Get to Work Careers (preferably Doctor career) and has a youtube channel talking about their career. It could delve into shoots away from their house where you build sets, or give them sponsorships and the like. I have never played this scenario but it sounds fun. Perhaps they could be in a club with the big stars in Get Famous (included the famous sims not in the world) and regularly meet up for drinks, events, parties, in their homes or in the hotspots. This idea might save you from going back to the actress career. You could start drama or start a Great Gabsy party life feel.
If its a family, perhaps the spouse could be prone to drinking(or have some interesting trait to them that leads to a not so perfect home) and the children might be bratty and entitled, and they might all have their specific clubs and play around with the reputation system.
Good luck with your new save~