Thank you so much ^^! The last two bonus events are unlocked the same way. Here's a step-by-step guide (SPOILERS):
-On Night 1 let Bemelle die, save Margret and save Lu
-Romance Lu (spend time with just him whenever possible and always be kind/reassuring)
-At the beginning of Night 2 when the Guide is in trouble, don't do anything, just let the timer run out. This is a major choice that sets you on a new story branch. Finding that opens up a fair amount of new possibilities, so you may want to try going through that story route blind for the first time to avoid spoilers. Or feel free to follow the rest of the steps outlined below.
-----------------------------------------------------------------------------------------
-Continue to romance Lu by letting him open up about himself
-Keep going and going no matter what happens
-When the guide goes to handle something on his own, have Kikka check on him
-And then continue on until the end of the game. There are one to two more choices that you'll get, but you can do whatever you want with those. Any of the four ending versions of that route will unlock the bonus events
The guide does have multiple endings, but none of them are great, aha. I can't say for sure if you romanced him properly or not because of that.
Good luck! I hope you'll enjoy the remaining content :D