Within the same time period (except for the reloads):

1) In Drezen, 2 Radiance swords: one is the original; the other is the cold iron +2 sword.
2) After resting, only Aivu was in the 'conference' room...no Irabeth, no 'hand' icon for managing crusade...had to reload.
3) After giving Irabeth Solemn Hour and getting the experience, I found the longsword in my inventory.
4) Upon going in the city, Drezen was empty: no NPCs, no team members, no Aivu....only my PC & pet.

Is anyone else encountering these issues? I'm playing 'Normal' with one exception: managing everyone's leveling up myself. My pc exceeds the recommended requirements.

YES! I had your #2 and #4 issues occur recently, while playing the game. And I was also stuck in Drezen at one point, without any door indicators within the city (i.e. you could not transition from the street setting to either the citadel or the main exit out of the city). I just reloaded the game, and then it was normal again. Fortunately, there have been no repeat occurrences of these issues.

I'm playing on Core Difficulty with no mods, BTW.