I also worked out a couple fixes specifically with the 2 replays in Chapter 3 for Kiara.
For the "Kiara played with fire" replay I was disappointed as it doesn't actually play the full scene, but only goes down the low lust path that ends immediately due to not using the actual values from the a playthrough. To counteract that, I added a menu in the _in_replay section to manually set the $kiara_lust value to the appropriate levels during the replay with descriptors of how the scene can go. I then made sure to go to all the possible paths and add $ renpy.end_replay() so the replay would actually end. You can now either bring it to the end of the scene or end early without issue.
With the"Kiara thanks you" replay the replay_setup.rpy appears to possibly be starting at the wrong spot. It's got the value of "chapter03_scene_04_01c1", but looking at the chapter03_scene04.rpy it looks like it should be "chapter03_scene_04_01c" as there's a if _in_replay: check there which can't be reached any other way and would add the exit button that doesn't appear in that particular replay since there isn't similar code at that 01c1 label. I also did the same fixes for manually setting the kiara_lust in this one's _in_replay section via menu and added any needed $ renpy.end_replay() to close out the replay.
MCK-Games just wanted to say hi there and absolutely loving this game so far! I had played through chapter 6 previously and restarted this weekend as I forgot a lot of what happened over time. Hopefully you haven't already fixed the issues here so this is useful for you as well. I'm totally ok with you using all or just part of these fixes as well. Obviously the menu might be excessive but I liked the concept of being able to vary it so I can see the scene how it went for me.