What It Does
Want to save your mother from Quentin?  This mod is for you.  This changes it so that Hawke arrives in time to rescue Leandra before she's been horribly murdered and turned into a Frankenstein's-Monster-Lady the game so charmingly refers to as "zombie mother."

How It Works
"All That Remains" will begin as normal.  However, when you arrive in the Killer's Lair, Leandra will no longer have the zombie headmorph, and she'll be dressed in normal noble clothing.  You will no longer fight a "Possession of Leandra."  There will be no death scene (which means you're going to have to kill an extra corpse that Hawke normally takes care of in the cutscene).  Instead, Leandra will follow you about until you leave the zone.  I added an exit to the zone directly to the left of the final confrontation area, so you don't have to walk all the way back through the Foundry.

The rest of the game will proceed as though Leandra was never kidnapped.  Gamlen won't talk to you about it, and your love interest (or Aveline) will not arrive to console you.  Leandra will return to the Hawke Estate after she has been rescued, and she will be present in Act 3.

I tried to eliminate every reference to her death from the game, but there may be some I missed, so if you stumble across any, let me know and I'll see what I can do!  (Exception: there's a line of Warden Bethany's that references missing Mother, but she also says she misses Hawke in the same sentence, so I let that one go.  Templar Carver also has a line that says "trouble found Mother" -- but since technically she was still kidnapped, I also left that one.)

Installation
Drop the ERF in your override.  Technically this can be installed any time prior to entering the Killer's Lair in All The Remains, but I'd recommend installing before the start of Act 2.

Compatibility
Eliminating references to Leandra's death meant tweaking a lot of files.  Wherever possible, I tried to avoid making changes that would conflict with other mods, but there are a couple that aren't fully compatible.  These are:

Repeatable Romance Scenes -- if you're using this mod, you'll need to download the compatibility patch and place the "dae000_pc_home_ambients.cnv" file in the "Custom Cutscenes" folder of Repeatable Romance Scenes in your Override, and overwrite when prompted. 

sapphim's Dialogue Mini Mods -- if you're using "Shut Up Gamlen," you'll need to download the compatibility patch and place it in your Override.

Unobtainable items fix -- if you're using this mod, Gascard's letter will still reference Leandra's death.  (Though if you remove the "Main Game" erf from its UIF folder into the main Override/into the same folder as Save the Day, my file should overrule it.)

This mod also alters one of the same files as Skip the Harvester, but you should be able to use the two mods together without needing a patch.

Leandra Outfit Replacers:  won't work on post-quest Leandra.  She's in normal Noble Clothing A.  I had to make a new Leandra to spawn in the Hawke Estate in Act 2, because for some inexplicable reason she kept changing her hair whenever I left the house.  Don't ask me why.  If you're using Dress Up With Mom, you can download the Dress Up With Mom optional file to work with her.

If you're using sapphim's mod to skip All That Remains entirely, this mod should (in theory) be able to be used alongside it to eliminate references to Leandra's death.

The full list of files altered by this mod is here:

Notes
Some of the Quentin cutscenes, particularly with Gascard, may come off as a little awkward, because I wanted to cut out allusions to Quentin already having completed his work.  He's still an evil necromancer who thinks Leandra looks like his dead wife, he just hasn't had the chance to do his murdering.  During the fight, Leandra will still look all wobbly -- but hey, he's using blood magic; she's allowed to wobble a little.  Hawke will still look horrified that Quentin has their mother, but a little horror is warranted!

There's no dialogue that would have really worked for a "hey, thanks for rescuing me" cutscene, so you'll have to headcanon your own reunion in there.

If you've got Gascard with you, and he survives (and I made it easier to convince him, because why not?) -- he'll still send you a package, but since his letter references Leandra's death, now you... just get a package.  Likewise, the "Visit Gamlen" quest in Act 3 now just tells you to visit him.

I had to get a little creative with some of the reference removal.  One of the banters between Fenris and Anders might not make total sense anymore (I think it still works, but YMMV).  And the Diplomatic response in the Visit Gamlen conversation is now a liiiiiiiiittle bit sassier, sorry.

Credits
sapphim's Dialogue Mini Mods - Shut Up Gamlen and Tlk Dump (could not have found death references without this!)
Sapphim's Tutorials - great resource for learning about plot and dialogue editing, which made this mod possible!
QuenchedSteel - various resources from their Modding Grab Bag, and Repeatable Romance Scenes