Quest flow
1) If you pick up the dagger before you're talking to LaD for the first time after accepting the quest, the journal entry that you found a dagger will suddenly pop up during this conversation, even though you found it earlier.

2) If you tell Gweiwen that you no longer want to be involved, LaD still asks you if you've informed her, even though the quest can't go anywhere at this point.

3) If you pick up the dagger, give it to LaD, then attack him, the script will add a second dagger to his inventory and you'll get two when he dies. I know that this is a silly thing for the player to do, but please fix this.

4) If Gweiwen has learned that LaD is dead, she should despawn when you leave and come back. She has no reason to stick around.

Objects
5) TR_m7_SlaveTrouble_note_b & TR_m7_SlaveTrouble_note_b_d: "With your help, I managed to lure Gweiwen and kill her. You kept your word in helping me lure her here." - these two sentences are clunky, repeating the words lure and help, and mostly overlapping in content. This should be shortened to just one sentence (or kept as two sentences, but with the second one just being "You kept your word.")

6) All the letters: "I just wanted to roam free" is a very weird way to describe escaping from slavery. It evokes more being tied down by family than actual "if she catches me I'll go back to being locked up". You should find a less stilted way to say this.

7) TR_m7_SlaveTrouble_amulet: The name would suggest that it fortifies Hand-to-hand, and that's what it says in your doc too. I assume you set it to the top skill on the list (Acrobatics) by accident.

TR_m7_SlaveTrouble_dagger:
8) You don't need to make a unique enchantment for the dagger. It's just a small poison effect, there's several generic enchantments already in vanilla or in Tamriel_Data that do almost the same thing. Pick one of those instead (search for enchantments called poison, venom, spider, viper...). Multiple weapons using the same enchant is normal (see how many use cruel flame_en), in-game it will be displayed with the name of the enchanted item.

9) Since it's enchanted, the dagger should have Ignores Normal Weapon Resistance ticked. This is not entirely consistent (neither in vanilla nor in PTR), but enchanted weapons being able to harm ghosts etc. seems to be the default assumption.

10) It has a higher Thrust and  Enchantment, and lower Health stat than the normal Chitin Dagger. Unless there's a particular reason, enchanted versions of generic items should retain the same stats (except value)

11) Speaking of value, 120 is unusually high. A whole steel sword with a poison enchantment is worth less.

NPCs
12) TR_m7_Long-Are-Days: He only has 17 skill in Short Blade. It should be at least in the 50s if this is the weapon he will attack the player or Gweiwen with. Similarly, he only has 11 skill in Unarmored, making him even worse of a fighter.

13) TR_m7_Gweiwen: Her base disposition is only 30. Since she needs 30 to say her quest greeting, there's a good chance players will never even find the quest if someone else knocks down her disposition. I would just give her the standard 50 base disposition that most NPCs have.

Scripts
14) TR_m7_NPC_Gweiwen: This script doesn't do anything that the generic T_ScNpc_Mw_Map7Nolore doesn't already cover. This is probably a relic from when the script on her had another function, but since it doesn't anymore, it should be removed in the final version.

15) TR_m7_NPC_Long-Are-Days: The command that sets TR_Map to 7 on him would pointlessly run over and over again, not just once. See your script on Gweiwen for how to do this correctly - there you have
if ( TR_Map == 7 )
    return
endif

set TR_Map to 7
and so it will only be done once.

Dialogue
16) You haven't added a latest rumor entry. That's part of the showcase requirements, to see that you can weave your own lines into existing topics and filter them correctly. Other people at Stormgate Pass (for whom it makes sense) should tell you that there's a slave catcher hanging around, and they should also have an alternative rumor for when she's gone. In your specific case, you'll probably need to also edit the "Cat-catchers steer clear of Stormgate Pass, in spite of its proximity to the border. Too scared to tussle with a squad of Legion-trained Argonians, I expect."-rumor, since that kinda contradicts your quest.

17) You use %PCRace A LOT. The problem with that is that it sounds very unnatural in certain cases. If the player and the speaker are the same race it's a bit weird in some contexts. It's especially weird with elves, because they generally call themselves -mer, but if you're playing as a Bosmer, Gweiwin will say "Greetings, Wood Elf." to you, which just sounds silly. I know vanilla didn't care most of the time, but we can do better. Try replacing those with another word or variable (like %PCclass), or just remove them. You can also add alternate lines filtered to Function SameRace if you think it fits really well. I know %PCRace is also in the letters and it'd be harder to change there, so it's fine if you leave it for those (an Argonian calling another Argonian "Argonian" is probably okay, as long as it isn't every other sentence).

18) It's not "the Black Marsh", it's just "Black Marsh".

19) It's not "Stormgate's Pass", it's just "Stormgate Pass".

20) You've used the phrase "surrender unarmed" a few times. Unarmed really is implied in surrender, and I'd remove the word.

22) [Lie] goes at the front of a choice, not at the back (and no full stop after it)

 
General
Long-Are-Days (the topic)
23) "the Census and Excise's precious time" - you need to make this "the Census and Excise OFFICE's precious time, or reword it.

24) The generic response at the inn starts three sentences in a row with "He". Try to vary your writing more.

Gweiwen
Greeting
25) "I understand." is weird for a greeting after you've gone and come back. It'd be better if you add a second sentence here that links up to the Long-Are-Days topic, so the player can immediately see which job she's talking about. "The job is up" is also not a fitting turn of phrase.

26) This line also still plays even if LaD is dead and you no longer have the topic to take the job.

27) If your journal is already set to 60 because you found the dagger, but haven't questioned LaD about it, Gweiwen will no longer greet you asking if you've found him, which doesn't make sense (you can still tell her that you found him just fine, though).

Long-Are-Days (the topic)
28) "get precious info" is a weird use of the word precious, in my opinion. It's also usually "information", although there's at least one vanilla instance of "info" too.

29) "pays well I asure you" - missing comma and typo

30) "to ask around the locals" - it's either "ask the locals" or "ask around".

31) You need to add some more information to Gweiwen's response for if you killed LaD after learning of his plan. She goes to "Thanks for saving my life" way too abruptly. If the lead-in choice is only saying "Yes", then you have to imply the player telling her more information in her response. Something like "so he was trying to ambush me? And attacked you?" etc.

32) "get an easy job for once" - wrong tense. Should be "I've got". You got it right in the other line.

33) "I'd definitely be more cautious approaching him" - "I'll", not "I'd"

34) "get him myself then" - missing a comma.

35) All the outcomes where she gives you a reward should also increase her disposition. Currently only the one where you learned of the ambush and killed LaD does.

Long-Are-Days (the NPC)
36) If you meet him before you have the quest topic, he will have no dialogue topics available at all. The same is true for certain quest stages. We try to avoid that, it makes NPCs look unfinished. At the very least he should have a simple Background entry that's always available, but responses to some other relevant topics are fine too. It adds character to quest NPCs.

Greeting
37) "once I finish my rest." - this should be rewritten to be less stilted.

38) "Let me rest for a bit more..." - This should be rephrased - if he's still pretending to be a traveling merchant, he wouldn't ask you to let him rest, why would that be any of your business?

inform Gweiwen
39) On the lines where you have "startcombat player", you should also have "setfight 100".

40) "Even with your gold, I'd soon run out of it." - find a less clunky way to phrase this. "Even if you give me gold, it'd soon run out", for example.

41) "I plan to ambush Gweiwen murder her" is missing a comma.

42) "I'll finally be free to journey wherever I'd like" this sounds a bit weird to me for when we're talking about an escape from slavery. His goal is to escape to Black Marsh, not just a vague aspiration to "travel freely".

43) "Nice." is a bit too much of an internet colloquialism - make that "Thank you."

Journal
44) "the hiding Argonian" sounds weird, and the qualifyer isn't necessary.

45) "dagger nearby the Argonian" - either nearby or near the Argonian, not both. The latter is preferable to add context.

46) "this dispute" is not a good way to refer to the situation. "more involved" is stilted as well.

47) Since entry 150 only triggers when you find the body it should mention that you found the body in the canyons, not just state that she's dead.