How do new buildings work, exactly?

[19iguy]

Brief summary of the story:

I had a household living in Bridgeport but later I decided to "copy" it into Starlight Shores, because that's how wealthy they were... Also Bridgeport was acting weird and buggy with Services. Couldn't make the Butler work. Anywho.

One of my sims was working as a level 10 Movie Director - but there is no studio in Starlight Shores (odd, considering Starlight Shores is basically Hollywood LA and whatnot).

I can add a Studio through Build Mode - but here's the question - who will be working in it?
Will my Sim be the sole employee there, since no other residents were assigned to that job when the "new game" began? That would be annoying.

Same question goes for the "potion seller" shop-thing I wanted to build in some other neighborhood - does nobody work there once it's placed?

[Sonshine]

I believe that the game assigns townies to jobs like your boss and co-workers or in the case of the potion shop, a cashier.

[Candyd]

Starlight Shores is the Showtime addon town, and it can only have base game and Showtime careers, it's normal. Not everyone has Late night and Showtime, so that's why you won't find careers from one addon in towns from another addon, unless if you place the corresponding building. It's a matter of compatibility.
Some townies will be randomly assigned a career in the studio. There will be more and more with time (but not many, usually 3 or 4), but if you want you can add the sims of your choice with cheats.
Same with the elixir store, a NPC will be generated to work as a cashier there.

[19iguy]

Starlight Shores is the Showtime addon town, and it can only have base game and Showtime careers, it's normal. Not everyone has Late night and Showtime, so that's why you won't find careers from one addon in towns from another addon, unless if you place the corresponding building. It's a matter of compatibility.
Some townies will be randomly assigned a career in the studio. There will be more and more with time (but not many, usually 3 or 4), but if you want you can add the sims of your choice with cheats.
Same with the elixir store, a NPC will be generated to work as a cashier there.

Thanks a lot, really clarifies things.
I know about the compatibility issue - just feels odd, is all. Didn't they add vampires "twice"? In Late Night and Supernatural, so people could go one or another - or both. Anyway, thanks for the answer.