Hey, great mod you have here.
So I have the Orchid Plant Care Station setup in the middle of my farms, which themselves are a bit far away from my main pop center. I was wondering why I wasn't getting any workers since I had plenty of Orchids lying around doing nothing. The area tooltip only says they need to have farms in range (some other buildings require houses in range to work). I fiddled with this a bit and noticed that the houses themselves have a range and give workers to gathering huts and the care station. I was thinking that this seems very weird - some buildings have an area of effect that require the workers and some will have a area of effect that do something else and then the houses area of effect enter in play.

I think this should be streamlined. The workers for some buildings (like the gathering huts and care stations) should just get the workers from wherever they are in the world (maybe you do a one time calculation when the worker is assigned to figure out their workhour per minute depending on distance so it isn't too op). You could leave some buildings still needing to have houses in range as per stated in their area of effect tooltip (i.e. the headquarter buildings for each caste). This would also remove the range from the houses which could be confusing: "do I need a house inside the range of the market or the other way around" kind of confusion.

Yes, that's how you say it. There are buildings like the Gathering Hut or the Orchid Plant Care Station, which need workers and have another range for another purpose (namely forest access and farms to boost). I'm not sure yet how to better display this concept.
I was thinking about displaying the ranges of nearby houses when the player is about to place a building which needs workers.

As of the Orchid Plant Care Station, I'm thinking about removing their workforce requirement. They seem too restrictive by needing to be both near farms and near houses with Orchids. And with the Bloomhouse there are already farms which needs workers.

Other than that I still like the idea of requiring some buildings to be near a city. It adds a logistical challenge.