Thank you for your detailed feedback! The fireplace is supposed to be lit on Day 4, but I accidentally messed up the villager's routine by making him follow a faster villager before going to light the fire. This is fixed in the next build.
I will admit that days 3-5 did not have developed villager routines because I added them 6 hours before the deadline. There are several moments I could've added to make them stand out, but I chose to put more time into polishing the ending and the general gameplay loop. I also wanted to add a day 6 but decided it would make the experience too slow. Glad you stuck it out till the end!