Well, I suppose you can only do some very basic whoring in a building without any special equipment, and even that won't be good since girls only have their own rooms which are useable but not perfect at all.
So,
- buildings are not 100% brothels, they are just buildings for entertainment. You can build a bar and a stripclub and make money without whoring at all, though not as much money as with all options at once.
- buildings have slots aka rooms for girls. And they will have a separate group of slots for specialization.
For example, our basic building has 2 rooms for girls and will have 1 slot for specialization. After you turn it into a half-decent brothel by building brothel specialization, you will have those 2 slots for brothel upgrades available. No bar, no stripclub, nothing. But it is an old shack with 2 rooms, so it makes sense.
Or you can build a bar for a start and have less money AND less troubles with dirt and rapes
In a more huge building you will build brothel+stripclub and will have more money and workers.
- cleaners and guards don't require specialization upgrades, since you can clean and guard anything.
- more jobs like sleazy waitress (after bar upgrades) that require waiting+strip skills. Singers, dancers, etc. And skills for them.
- advertising, besides default options like sign, probably should be done by your girls as well. I mean advertising jobs and upgrades for them.
- If managers will need a slot specialization, then it will be pointless to build it in small buildings. Just like it's pointless to hire a manager irl in very small companies with 2 employees. So let's do it.