1) That's weird because I'm finding weapons in the durability settings I have. Do you have other mods that affect weapons? Is the "change gear for this group" setting -false-? (I've done that. Tweaked setting after setting, looking for a bug or thinking I didn't understand the setting itself, only to find out I forgot to "turn it on")
2) The "Min/Max Armor Class Value" setting is pretty self explanatory. The 1st number is the minimum/lowest armor class you want them to have, while the 2nd number is the maximum/highest armor class you want them to have. Be it for scavs, raiders, or PMCs.
3) The weight system is a bit confusing, but here is how I think it works. Using the previous setting as a guide (which armor classes you want the AI to have), choose a number between 1 - 6 (using the old name and example as a guide) to determine how each class is weighed. It's a weird term, I know. It's described as giving that class of armor X chance to be spawned on an AI. Just think of it as a form of "priority". The lower the number, the lower the priority when it comes to the game handing out gear when the AI is spawned.
The number itself, within the algorithm, means that AI (scav/raider/PMC) has that level of chance or is "X times more likely" to be given that class of armor when compared to others. 2 = 2x likely, 3 = 3x likely, and so on. There are 6 slots, each according to the armor class from 1 - 6 in order. FYI - When numbering them, you don't have to choose which one is priority 4 and which is priority 2. If the min/max class range is 1-3, you can "weigh" class 2 above the others by giving it a higher number, such as 2, 4, 2. And using that example, having class 1 and class 3 at the same priority or weight means the AI has equal chance to spawn with either, but less than class 2.
For my own sanity and ease of understanding how each class in the range given is able to spawn, I simply gave each class it's own number in its chance to spawn on an AI. Class 2 has 2x chance, class 4 has 4x chance, and so on. How you choose to it is up to you. You could have scavs more likely to spawn in with class 2 than class 4, if both of those classes are within the min/max range setting.
And as the description says, you can't "weigh" an armor class that isn't within the min/max class setting above it. It's been "removed" from the spawn list.
FIN - If I'm wrong in my explanation, I apologize. This is simply how I understand it and it seems to give me the results I want in the game.