* as the Dark Urge
Maybe you just love her music? Maybe you just want the Potent Robes? (so greedy! lol) Either way, for a knockout route, this is the only one I've been able to replicate consistently. It requires Shadowheart in the party, or a character who can cast the second lvl spell "Hold Person" to be reliable.
Step 1 Night 1: When you first hit the beach, go to camp after the Intellect Devourers area (just to get it out of the way, and for the camp discovery sequence to play if you want to see it) but then immediately head to the Dank Crypt rather than doing the fight with Goblins at the Gate.
Step 2 Night 2: Complete the Dank Crypt to unlock Withers and then run the Gate fight, do whatever at the Grove just don't interact with Alfira. Hold off on heading to the Blighted Village for now. Dodge Brynna, Andric and Astarion's boar along that route, in case another rest is needed you can go back underground at the Dank Crypt. Depending on the companions this rest will give a companion scene with some banter. The Astarion bite scene is the only one that sometimes haunts me here, if it happens you can go underground again to get that rest out of the way. I'm pretty sure it only triggers if you've run across the boar and had that exchange. If you don't want/need to sleep to complete the Crypt you can start the rest cycle here, or kick the can one more night. I usually do the Nettie and Arabella stuff first unless I'm very uninspired and just hit spacebar a thousand times for grove convos you've heard before. The important thing is to time the first use of Illithid wisdom with the Alfira knockout so that they will coincide on the same long rest.
Step 3 Night 3: Activate Passive Non-Lethal Attacks. Return to the Grove and talk to Alfira. After completing the dialogue, cast hold person (with Shadowheart) until it lands. If it fails re-class at Withers to restore the spellslot and try again for a cost in gold. Once Held enter TB mode and knockout Alfira - then exit TB mode and warp to the Emerald Grove waypoint. From here go to Andric and Brynna or the Blighted Village and use Illithid Wisdom on the Gobbo to prompt the tadpole dialogue among the companions. Now when you long rest you should get the Quill scene.
Earliest I've been able to get this scene is on Night 3. Kicking the can Alfira still shows up early sometimes if I camp above ground, or push the long rest until after the tadpole scene. She can show up at Camp even if you've haven't seen or interacted with her yet which is why I like to use the Crypt. Through trial and error I think that's the main thing that prompts the sequence, the first use of Illithid wisdom and then camping outside in the open. It jumps that camp scene to the top of the queue, or at least seems to be what happens for me. If something goes awry and you get a different Long rest scene first, just knock out Alfira again using the same method as before long resting again the next night. Repeat until Quill shows up. Without Hold Person you can do the same, but Alfira will drop Attitude with each attack. Too many hits will call over Lakrissa or Arron, or both and send the grove temp aggro. Alfira will heal outside of initiative and move around, so hold person just seems better. It gives that autocrit so usually only one turn to knockout. This way it's as if it never happened. She'll show up at camp friendly and you can still do all the 'save the Tieflings' type stuff. If attitude drops too low (not using hold person) she will still show up at the camp celebration but won't speak. I think she resets at the Last Light regardless, but hold person is best. Low risk, for the Honour! lol. Same sorta thing works for Minthara if trying for that too, just gotta watch out for the goblin with the acid vial which can get hectic. With Alfira though it should be no issues, since there's no one else around in that corner of the Emerald Grove unless you make a big ruckus.
Not sure if there's a better method?
Anyhow that's the one I like. For honour it's basically eating those bonus camp supplies to do the early long rests and just calling it a wash hehe
Let me know if there's a better sequence, or another route with fewer snoozes. If going for a resist the Dark Urge theme I usually do it this way - using the inspiration on Arabella first if needed, but avoiding the path up to Alfira on the lefthand side just beyond Volo. After Arabella and Alfira are saved, whatever inspiration we banked or didn't use there can be spent on Scratch or Lump just to be sure. Once the tadpole stuff plays out, I like to go for the Owlbear or Harpy fight to celebrate if it works. For regular Durge, you can arbitrarily save some Tiefs and still go pretty evil in Act II. Just depends on what you're after.
Good luck out there!