Woo, I hope you are enjoying the game so far! (At least I hope!)
The Christmas stuff was a lot of extra work, but it was work I enjoyed doing~ There's a few Easter eggs like that~ (though no actual Easter event)
And yeah, the combat crash thing... happens. Sadly it seems it's a memory overflow error that is inherent with the engine and becomes more likely to occur the more you add to the system. I had hoped it was gone after not running into it for 2 playthrough but seems like nope! Still there. It seems to occur more when you have certain programs running in the background too. But nothing I can do about it... Sorry!
I'm still enjoying it on the second run, yes. :-)
I think I can confirm that Malayna's bugged vengeance message is fixed. Celeste has fallen multiple times when Malayna's relationship score was high enough to trigger the bug, and we haven't seen it happen. That's a good sign. It will be a bit longer before I can confirm that the later battle lockup is also fixed.
Laetitia wouldn't happen to use the same battle engine as Luxaren Allure, would it? I ask because LA had a very similar issue with battles crashing, but a fix was eventually found (long after I'd finished the game, sadly, but I was tracking the thread for other reasons). I don't know if the same fix would work for Laetitia, but maybe it's worth a shot?