Arise, o deceased thread!
Thought it might be worth posting my approach to this. I had lineup changes leave me with two ex-PCs at one point, and it was during the fire forest so they really had little chance to leave for most of that adventure, so I got REALLY fed up with DMPCs at one point, despite the first entry below.
TORRENT - Did most of the initial infodump, then died in mid-sentence to the very first Ragesian bomb to hit Gate Pass. Pretty much for Zinovia's reasons. Remaining info and supplies they needed from her were found in her conveniently unharmed backpack.
HADDIN - Persuaded to tag along by flattering him (well, and by an Inquisitor literally showing up at his front door - Haddin was egotistical enough to think it was him they were after, in fact I think some of the party thought this too). Later, overplayed his hand by teaming up with Kazyk and openly turning on the party. Died as a result; this was the expected and hoped-for result, didn't have to fudge the dice at all to arrange it.
KRYSTIN - Was actually more initially interested in going along than Haddin, but backed down as soon as he objected and so was openly pleased when he changed his mind (Haddin didn't like that, nor any sign of her having a mind of her own). Sat out the fight where Haddin turned; that left her in a horrible place psychologically, as she comes to fully understand what this man she depended on was doing to her. (Ryan says he was meant to be abusing her sexually, even he wasn't he was still controlling her - Haddin was a horrible person and that can't be an easy thing to realize about your father, especially for someone like Krystin.) Became suicidally depressed, and talking her down and keeping her that way has become a minor sub-plot. Dramatically she's a lot more interesting with Haddin dead than alive. Future unknown even to me at this point, but distinctly on the mend, thanks in no small part to (just the way the dice fell) kicking ass during the rescue of...
KATRINA - The group LOVES her. Doesn't trust her an inch, and rightly not at this point, but they seem to be thoroughly enjoying her. Will definitely be around on and off for the foreseeable future. Or (once she's more sincerely on their side) I might have some villain I really want them to hate kill her off. You never know.
TILJAN - is actually a PC! I brought in a guest co-DM, a friend of most of my players who sometimes runs short-term World of Darkness games that have gotten much praise, to handle some of the NPCs in the second adventure. So she knew the second adventure well enough to be correcting me on some of the backstory, but nothing about the rest of the story or the world - which was fine, that's exactly the position the character is in. All concerned ended up enjoying her contributions so much that she asked to stay with the group permanently, and we rebuilt Tiljan for her to continue using (though she also has a druid she'd like to bring in should Tiljan leave or die).
And looking ahead a bit...
THREE WEEPING RAVENS - Also a PC. Or rather, will be replaced by one. Those two departed PCs I mentioned above were associated with the Monastery of the Two Winds; the plan is for one of them to come back, ideally played by his original player, and take the part in the story that 3WR does in the path as written.