Thank you. ^^
The christmas bonus was, as the name implies, a bonus scene I added during christmas. It's not possible to unlock it at the moment, but I'll likely make the former scenes available again next christmas together with hopefully some new bonus content. :D
The walkthrough is not outdated anymore, even if people keep saying that. Q_Q But it's still lacking some details.
In general use present items to improve the relationship with characters and regularly try to talk with them at the sleeping chambers for new events. If you want more details for several specific scenes I'd suggest trying to ask for help on discord at https://discord.gg/A79WrBq where I'm always available when I'm online. :)