OKAY... i think for dagger ending au i'm putting the game events in a very specific order.... siffrin finished kingquest before the friendquests because they were focusing on one quest at a time, because if they tried to look for too many things at once they wouldn't do a very good job looking for any of them? like wait i remembered to look for x in that room but i forgot to look for y, umm i think i have no idea which rooms i actually searched for what.
so he locked in on kingquest first, with loop hangout part way through it. and then he poked around for stuff to read in the forgotten language now that he could read it, but he didn't know enough about wishcraft to make sense of it. he did go into the locked star room, but didn't read the diary (bc he won't until after friend quests bc the stars make him sad). so he was pretty stuck on loop quest at that point, so he finally turned his focus to his friends: first mira, then bonnie, then odile — and happening upon the right papers to find that familytale took a whiile — and ofc finally isabeau.
then the perfect family run didn't work and they were devastateddd. what now!!?! they went through the house a couple more times with friend quests completed, got sick of those and switched to just skipping around the house checking this and that. finally they went all the way back to dormont again to talk to loop in person, and the two of them decided they should try checking the forgotten language books again. the ones they found didn't make much sense, but one of them was in the secret library right? maybe there's others hiding somewhere in there too? (<- said in the tone of someone who is checking the freezer for their phone because hey, why not try it now that we've exhausted everything that would make sense.) and that's why siffrin was planning to loop straight to floor 2 — they had a mission, and they were done doing everything in dormont, it doesn't help, it's just manipulating their family for their own benefit.
and that's where we get the au divergence!
so in that final run through the house, siffrin knew that the king had mentioned wish craft, but nothing else about it. they were taking their time and having the long versions of conversations and rereading everything (outside of dead-ends), which includes:
the craftonomy book - they discuss how the king is using time craft, which would normally kill someone
the newspapers - they discuss the king's origins and the stars on his armor
the sparkly diary - they discuss the forgotten island, and siffrin asks isabeau to try saying it
the letter - siffrin talks about running away from home, and trails off
and, now that siffrin has completed the friendquests and is checking every single little thing for the first time since then, he finally opens up the star room's diary and has his family read it for the first time! since they haven't read the forgotten language books about wish craft, isabeau and odile dismiss it as fiction. siffrin, though, feels like he understands wish craft better. and in this au, where he's been feeling very stuck but now suddenly desperately wants to stay in this version of the day in a deeper way than ever before, he starts to wonder if there's a way he could make a wish to get out, somehow. but he still has no idea how wish craft works.
and then he doesn't need to follow up on that, because that's the last loop!
also, here's the sus points they got, in addition to yknow the whole conceit of the au and the effects that would have on their behavior the next day.
When picking up the Circle Key, choose "What's up with the circles?" and then "The Universe."
Activate the switch in the Death Corridor.
Enter the right side hallway on the first floor proper with Siffrin 20 or more levels above the rest of the party.
Interact with the first tear in the right side hallway.
Interact with the dictionary in the locked Storage Room.
Bump into the counter in the Kitchen after already bumping into it five times in previous loops.
Interact with the cutlery closet in the Break Room in a loop without Odile's Friendquest completed.
In the right side hallway at the row of tears, choose either the Age Alliance or the Beauty Alliance.
When reading the Sparkly Diary in the Library, choose "But can you try and say it anyway?"
Choose "Wow, a secret passage~!" when opening the path to the Secret Library.
Interact with the book on shields on the very right bookshelf in the Secret Library.
Open the star-shaped door using Memory of Memories.
Interact with the orrery in the room behind the star-shaped door on the same loop as looking at the newspapers in the Writing Dorm on Floor 1.
Interact with the hair-covered door before obtaining the KeyKnife.
notably this doesn't include any of the points you get by skipping conversations or events, interacting with equipment you already own, or reading the forgotten language books on wish craft. and without that last one, no sus event.