I've used the guides and now have clean neighbourhoods. However, I'd like to populate them with my own sims as townies/playables and make my own lots. I want to have Takemizu Village be mostly Japanese characters/names. This includes the hotel workers (if possible), townies, and a few playables. Same thoughts as the other neighbourhoods - Uni, Bon Voyage, OfB, Nightlife, etc. I want to create my own hobby lots and sims that go with it. I want to create my own pets/strays. I want these sims to come with every instance of the sub neighbourhood I create in different save files. I don't want to have to put down the lots and sims every time I create a new save. If I could, setting their jobs/skills/friends/partners would be amazing too but I'll settle with "blank" sims if I have to. haha

Is there some way for me to do this? Every google search just tell me how to put down a lot and have the sim buy it or to put a sims in another neighbourhood, like I'm brand new. lmao

It is possible to populate Takemizu Village with any townies. They go into family number 7FF3. Same with stray pets. Downtown has its own family. You only need to use a people maker mod to accomplish this.

The other tasks would require a game mod. By default, not all NPC roles respect the Familiar NPC token that would associate them with a lot, or any mechanism to associate them with a neighborhood. In my game I also aim to have a "Focused Population" limited to the current neighborhood, and I make new NPCs when I get an inspiration. For this, I made a private mod that works only on FreeTime. Without a mod you can't keep hotel workers or other NPCs from crossing neighborhoods.

I don't know how to build on hobby lots. I think you temporarily need to change their zoning and hidden status with Sim Pe. You will find a guide for this if you search.

While it is possible to put some townies in a neighborhood template, there are two problems. Their names will get mangled upon import. And the townies will merge with other townies unless a mod marks them as distinct. So you cannot have Bluwater townies and Pleasantview townies.

I have made sets of vacation townies, including ones with Japanese-y name/style for Takemizu. Here are the Asian ones:
https://www.pillowfort.social/posts/1941340

In case you prefer to make your own, I also made a tutorial, which you might like to try out...
https://www.pillowfort.social/posts/1949290