Finally, something I can give my completely unwarranted opinion on: K.K. music recs
For a spa, the obvious choice would be a song with ancient eastern musical elements, or using old eastern instruments, as pretty much all items that could be used for a spa in this game are very clearly onsen-inspired... and I'm just gonna assume that your spa area therefore looks like a japanese onsen. But it'd have to be a calm song, so therefore I'd choose... Stale Cupcakes. There isn't really a song that fills the "traditional japanese but downtempo" niche, to me, Spring Blossoms just sounds too upbeat for an area like that. If it were up to me I would probably just ditch music altogether, and only let the sounds of the water (do diffusers make noise?) carry the atmosphere. But it's all up to you
For a café, I will NOT rec you Café K.K., because that's what everyone and their mama is using. I also don't even know what kind of café you've designed, so a Parisian melody might not even be a good fit altogether. I like K.K. Calypso, and not a lot of people use it because it reminds them of a tropical region, but to me, it could pass for a café song? K.K. Moody goes in that "European" direction for me, but could be an alternative to Café K.K. And besides, if you really wanted elegant European highstreet music, Animal City does it best.
A quieter song with a minimalist melody and lots of "space" in the instrumental would lend a forest area well, because then you can still pick up on the atmospheric sounds you'd obviously have going on in that area, without having to question why there's music blaring in a forest outside and having your immersion broken because of this (this is a direct callout to the gross hourly music that drowns out all the spectacular sound design that this game has)
I like Farewell, though it's a bit on the melodic side. However, there's not a whole lot going on at a time, so it'll blend in well with the sounds of the forest. I can imagine this sounding especially beautiful during rain.
If you want nostalgia, and especially if you're using the dirt path by denim_2mori, you'd might want to try Forest Life. I'd personally love to hear that outdoors in a woodsy town. Another song that'd go well in rain. Last rec would be K.K. Stroll, but that's a given considering the name.
Zen garden-wise, I would rec K.K. Condor. Yes, not the same region at ALL, but to me it has a similar feeling to all the ancient japanese melodies in the game, while simultaneously being a bit "out there" and unique. Another one would be K.K. Folk.
For some reason, I hear the beginning of K.K. Aria and immediately think of how a song sounds when it's played while you're underwater. Is that just me? I think it makes for a very good mermaid song, probably the most fitting song out of all... because none of them can really be classified as "a mermaid song", like what would a mermaid song even sound like
For the hotel lobby I'm picking K.K. Cruisin' because we're at the end of the list and I haven't had the chance to rec K.K. Cruisin' yet. I don't know about you guys, but if you played me K.K. Cruisin' in a hotel lobby I'd stay one night extra. That's a 5-star song right there. And it's like just chill and elegant, yet modern and exciting enough that it would work for a hotel on the pricier side that still sees a lot of guests.
Alternative Option: Two Days Ago, because it evokes a similar feeling in me.
Yes, I wrote a novel. Yes, I take this very seriously. Also stan K.K. Cruisin'
