Fixed.
For future reference, I also fixed an issue where Irus was speaking in quest feedback instead of directly to the player.
Fixed.
This is actually the 3rd quest, not the fourth. I see what you mean, though; there were some steps deleted in that quest but the actual dependencies for said steps were never updated, so the instant you spoke to the NPC, the quest ended. Either way, fixed.
Fixed.
Fixed. (You're right on that assumption, by the way)
Thank you for your testing!