In doing my prep for this adventure, I've noticed that there's a whole slew of NPCs that are meant to be used as-is, despite the fact that, by default, they wear medium or heavy armor, which the adventure seems to frown upon. I'm talking about all the guards, veterans, priests, and so on. There's all manner of people trekking around the jungle - or sweating it out in forts and town houses - in chain shirts or splint armor.
And yet, conversely, we have a side quest in which the PCs are encouraged to encourage the NPC to get rid of her chain shirt. And we are told that anyone wearing medium or heavy armor has disadvantage on Con saves to avoid heat-related exhaustion.
I know I said earlier in this thread that I was going to make it so folks like Liara Portyr have armor enchanted with the temperate minor property, so they can wear medium or heavy armor and still be OK in the heat, but what about all these other folks? Surely they can't *all* have enchanted armor, nor can we necessarily say that, because many of them are native, or at least have been in Chult for a long time, they've gotten accustomed enough to the heat to be able to stand wearing heavier armor.
It's one thing for a firenewt to wear a chain shirt, since they're immune to fire damage, which also makes them immune to the effects of extreme heat, but I feel like it's another thing entirely for a creature like Queen Grabstab, who is supposed to use the goblin boss stats, to be wearing one.
The reason this has stood out for me is because I've been trying to discourage my players from having their PCs wear any armor, even light armor, when they get to the jungle ... and yet, if I've got all these soldiers and goblins and whatever else running around in breastplates and chain shirts and things, they're going to cry foul.
[/rant]
p.s. On a completely unrelated note, I just wanted to point out that the adventure doesn't specify what kind of naga Ukurlahmu was before the yuan-ti turned him into an undead one. According to the statblock in the MM, you're supposed to give a bone naga different spells depending on whether it was a guardian naga or a spirit naga in life. I chose the latter for my game, although it could be interesting to go with the former and have Ukurlahmu be related to Saja N'Baza of Orolunga somehow.