Might be interesting to share how we arrange our buildings and why...

This is my top floor...  since I manually assign idols to doctors, this lets me see all my doctors at once.  The managers are on the next floor, at the bottom of the screen, so I can see when a business opportunity arises.

A shot of the middle...  Here are all my active worker bees (Producer, Manager, Dance, and Song) so I can assign singles/media/events all on one screen.

Down at the bottom are trainers, set to auto train, along with a break room.

Interesting.

My setup is not that much different than yours, except that it's much smaller for a while still. For some reason, my game stalled, and I couldn't reach concert stages.

Anyway, I think the best and probably only viable way to start the game (without going neck-deep into debt) is :

L0 - PRODUCER  - MANAGER - MANAGER - REST ROOM

This keeps the costs lowest, since you won't have to spend money on spa to give your idols some well deserved break. You also get and need (!) two managers to fetch business proposals, given how much they can fail at lower levels of their "deal" skill, and one of them will also need to assist you with producing or researching.

After that, I'd recommend to acquire financial stability (through ads) before even considering dancing or recording studios.

Below that, I built the following, in order :

L1 - MANAGER - DANCING (cheaper) - RECORDING

At that stage, I could finally produce Singles for the idols, and the real game seemed to begin.

I managed to build :

L2 - AESTHETICIAN - DOCTOR

and recruit 10 idols before my time gauge stopped progressing (and the game stalled).