Now that’s some completionist dedication! Let me consult the inner workings of my code and see if I can help with these…
The game’s been out a while, but I’ll spoiler blur some of this.
Duelist - This one is difficult to get (by design, Lucia’s good at swordplay!) You’ve got the gist of it. In Chapter 6, go see Lucia (rather than Alice or Ioco) when the chance arises. You’ll need a Resilience stat of 58+, OR Panache of 58+. If you’ve got the former, choose “I’ll stay on the defensive.” If you’ve got the Panache, choose “Friendly practice? Never!” The achievement should pop on the next page.
Out of Ashes - To get this one, you first need to screw up a bit! So, by Chapter 10 you need the Infection Level to be 62+ (you’ve replayed a lot, so you can probably intentionally mess things up enough to achieve this - let Eustace fall off the Sanctuary roof in Chapter 2, leave the Sanctuary open for visitors in Chapter 3, stuff like that). You’ll then be shunted into the “oh dear, the Baron is going to burn the town down” ending. Choose any of the “we’re going to try to escape” options, and you should wind up guiding at least a few people to safety. The achievement should pop up in the epilogue.
Medical Error - This is a super, super rare one. It’s a very specific and narrow path (that’s my fault, looking at this now I’m amazed anybody has got it at all). I’ll try to reverse engineer this as best I can…
In Chapter 8, make you sure you mess up gathering the lichen in the caves. You need lower than 52 in whichever stat you try with (so just make sure you’re crap at Mysticism or something, then use that).
However, you will still need to know enough about the plague to identify the source correctly. The Sourcing the Contagion stat needs to be 58 by the end of Chapter 9.
In Chapter 11, when dealing with the food dilemma for the population, try to mess it up. The easiest way (if Sibyl is still mayor) is to be too ruthless for the compassionate “come on, share some food” choice, or too populist for “they can owe you with future earnings” option. If you relationship with Sibyl is lower than 55 these will fail too. If someone else is mayor, either be too feudalist for “requisition the food!” or not opportunistic enough for “give people food in return for joining the militia”. Again, having a relationship of lower than 55 with whoever is in charge will also fail these. If your compassion stat is 46%, you can also do the “triage approach” - that should fail as well. It’ll become clear why you want to do this in a bit …
Then, later in Chapter 11, when you’re researching with Alice, or examining bodies with Ioco, or doing Mystic Dweller Things, or relying on your recruits, you need to have high enough stats to figure out “oh, we could make an inoculation”. That’s either 60 Physician or 60 relationship with Alice (Alice route), 60 Surgeon or 60 with Ioco (Ioco), 60 Mysticism or the Dweller’s Mark (Mystic route), or at least 6 medical recruits (recruits route).
I told you it was involved … okay, so, you should then be able to choose to try to develop an inoculation. Since you only retrieved small amounts of the lichen (Chapter 8), you’ll be able to choose to use what little you have left on yourselves or “Prepare what few does we can”.
Then! (whew), in Chapter 12 you should get a scene where you’re in the Sanctuary basement doling out the vaccine. This is the penultimate hurdle, and where things get a bit tricky. For the inoculation to be semi-fatal, you need Sourcing the Contagion to be 57 or lower. But what’s that, you say? It needed to be 58 or more earlier on to even begin this sequence? … yes, it did. I think that’s a bit of a design flaw on my part. But! You can make this work. Remember when you screwed up with food distribution in Chapter 11? That’ll give you a 15% penalty to the Contagion Source stat (because people are starving), which HOPEFULLY puts you back under 58.
If the above sequence works out correctly (you might have to try this several times, I’m so sorry), then you will be inoculating people in the basement, the inoculation will go wrong, and you will have the chance to cover up the error. A stat of 60+ in anything except Mysticism (there isn’t an option for that) will be enough to succeed, as long as you pick the right corresponding choice (so, lying is Panache, blocking the door is Resilience, the medical one is Physician OR Surgeon, and the threats one is Presence).
Then the achievement should trigger. Easy, right? 
Near Miss - This one is a BIT more straightforward. You need to create a cure with unfortunate side effects. Two ways to go about that - in Chapter 12, when settling on a cure method; if you have the creepy, silent monks hanging around in your cellar, you can try to make a cure from their blood, or (easier, since it will always be an option), go with “Our knowledge is slim, but if we combine what we know…”
For the achievement, you need to fail but not TOO badly. On the blood cure route, that means having a Plague Cure stat of at least 53, but LOWER than 60. For the power of friendship (and luck) route, you’ll be wanting Alice and Ioco at 52+ OR Plague Cure at 55+, but lower than Alice and Ioco at 55+ or the Plague Cure at 60+.
Again though, this one is a narrow path.
Final Bargain - Appropriately, this is the final one! For this, you need to reach the end of Chapter 12 where you’re presenting everything to the Baron, and have him condemn you to death. You will also need a Panache of 60+, no other stat will work. Having a low Crown Favor (below 65) should do the trick. Do NOT try to bluff him, because having high Panache can actually help you succeed there.
Then, when condemned, do the “Plead for clemency” option. Your Panache will talk the Baron around, and the achievement should pop.
I hope that’s enough of a guide for you! The ‘Medical Error’ one is honestly kind of absurd, and I really shouldn’t have tied an achievement to such a fringe result. I’ll know better for my next game…
