Surprisingly good writing and character development for an adult game. Kudos for that!
Some thoughts:
1) Greater weight for decisions. For instance, if one of the tenants asks for a relief from rent, as of now it's a very simple choice to just say "Of course!" It would be more challenging if, however, there were costs associated with running the 'hotel' and someone's daily income was lost. Each resident should increase food and maintenance costs, offset naturally by their daily (or weekly) rent. That way you might be able to go without rent from a few of the girls, but as more of them start asking for a break you may be forced to make decisions about who you're willing to cut some slack for. Which of course would then cause some tension ("You aren't charging rent for x but you are for me?" etc).
2) More ways to generate income, to help off-set the above. Opening the sauna, perhaps, for day visitors, which may occasionally result in a loss of affection from one of the residents but can increase revenue. Or renting out Lin or the Android for a day of labor, after meeting the prequisite obedience, and at a risk of losing some obedience in exchange. Or renting out the spare rooms before you fill them, which would help for the early game but dry up as you gain all the currently implemented residents.
3) More friction, where you can't please both parties, or making an unwelcome decision now but which may improve things later versus a welcome decision now with potentially worse results later. For instance, you may intervene in a fight or disagreement between two people that results in one (or both) losing affection, but will later unlock an extra scene as one (or both) later reflect on what you said, admit fault, and become closer. But if you instead choose to not upset anyone, their differences won't get resolved, and that later scene will instead be replaced with them having yet another disagreement.
In a similar vein, there are numerous story points where you may say or do something that someone is clearly unhappy with, but which still results in an increase in friendship. I know this is a way of monitoring your story progress with that person, but it feels off-putting to seriously upset someone only for it to result in your friendship to increase with that person. It would make more sense for there to be decision points where you'll receive a temporary malus to your friendship or affection, but which will help that character grow in the long term. Or maybe just the term "Friendship" should be replaced by something more neutral and descriptive like "Relationship Progress"?
Either way, I'd like to see a lot more of these scenes (and the game generally) have a bigger impact on character's affection score. As is, there are very few relationships that require any kind of additional effort (e.g. going on dates, spending time with them, etc) to improve their affection scores and progress their story arcs. With more ways for affection to be reduced, it would become more important to manage your time effectively to give each person attention that you wish to progress with. As is, there is a lot of "down time" where you have nothing really to accomplish in a certain time block. If more "relationship maintenance" was needed, these down times would feel more valuable.
Anyway, good job, and looking forward to more content and story!