Force Greet packages breaks when actors are added to Aliases
Ok, here's the reason why Force Greet packages in the Forsworn Conspiracy quest lines sometimes works (e.g. the guard that intimidates you outside the inn after acquiring Margret's journal) and sometimes fails (e.g. Dryston who starts a brawl with you after acquiring Weylin's note outside The Warrens and the guard that ambushes you in Talos' shrine when you return to Eltrys).

Actors' Force Greet packages may fail if they are added to an Alias - even if that Alias has no attached packages. Adding actors to an Alias forces them to evaluate their AI. This is what's making the actors in this quest (and possibly others constructed similarly) to not Force Greet the player. Eventually the actors will re-acquire those failed Force Greet packages when they next evaluate their AI.

HOWEVER, some actors (e.g. intimidating guard outside of the inn, Dryston, Nepos' maid, the ambushing guard in Talos' shrine) in the Forsworn Conspiracy need to Force Greet the player immediately after entering and exiting an interior cell. Because these actors may move away (and they actually do) from their intended locations, they may not reacquire the failed Force Greet package. Regardless, actors Force Greeting the player much later in time may eventually get the quest running again, it is not usually ideal.

Here's my test save with Wet and Cold. The save-file contains only the DLCs, unofficial patches, Live Another Life, and Wet and Cold. And here's my description of the test in Wet and Cold's thread. I've already notified, Isoku, via PM of this.

Unaffected Actors
Anyway...Actors who don't need to move to the player (immediately after an interior-exterior cell-change) to enact their Force Greet on the player works because the player is immediately "there" and the package triggers immediately. The intimidating guard outside of the inn (after you acquire Margret's journal) is an example of these actors. He never fails to Force Greet the player because his package triggers immediately BEFORE any of my mods add him to any Aliases.

Affected Actors
Actors who do need to move to the player (immediately after an interior-exterior cell-change) to enact their Force Greet on the player fails because mods that adds their effects on NPCs by adding them to Aliases would have added them to their Aliases. Examples of these actors are Dryston, Nepos' maid and the ambushing guard in Talos' shrine. These actors are added to Aliases before they could Force Greet the player - which breaks their Force Greet package. Again, they may eventually reacquire these failed Force Greet packages but its unlikely due to other Conditions (e.g. location, Quest stage, etc.).

Note that the owning Quests' Priorities don't matter in this case. My mod's quests that finds NPCs all have a priority of 0 while most of the quests in the Forsworn Conspiracy have a priority of 60. Also, it doesn't matter whether the Alias they are getting added to have a Package or not. The simple event of adding them to the Alias fails these Force Greet packages. Again, actors may reacquire these failed Force Greet packages when they re-evaluate their AI in regards to their attached Quests' Priorities. But by then, other conditions may have removed those Force Greet packages already.

Affected mods
Mods that forces these actors to fail their Force Greet are mods that finds actors by adding them to aliases. My mods that are affected by these are: Battle Fatigue and Injuries, Fight or Fly, Gold Adjustment, NPC Reactions, Sightless Senses, Skill-based Damage Multipliers, Useful Potions. I'm sure there are other mods out that will similarly break these types of quests. One of them is, as described above, Wet and Cold. It adds its effects to NPCs by adding actors near the player to Aliases.

The fix
And this is how to fix these mods.

In the Aliases' Conditions for finding the actors, add three conditions:

• IsInScene == 0 (e.g. Nepos' maid's Force Greet package is attached to a scene. My mods have already done this since their first releases.)
• GetDistance (Player) > 1500 (This is the important Condition. It ensures that actors nearby has a chance to enact their Packages.)
• GetDistance (Player) < 10000 (Use whatever distance you normally use to find actors.)
  

• IsInCombat == 1 OR
• GetDistance (Player) > 1500 AND
• IsInCombat == 1 OR
• GetDistance (Player) < 10000