The Candlekeep Collection - seeking feedback on this mod idea (spoilers)

(Note: I originally posted this in General Modding > BGEE, and it isn't getting responses there. But this is really more about gauging whether the mod concept offends sensibilities for the end-user, not how to mod it. I'll move this thread back to BGEE mods eventually, but I do want to get a sense from the player base what they think about it.)

Just as a lark I created the Candlekeep Collection to be used for a MP game to provide a tactical challenge. But that got me thinking that one day as a future project I might try to get some further practice with mod-making by taking the next step with this, and add the characters I created as joinable NPCs. They are:

Bendalis
Carbos
Dreppin
Erik
Fuller
Hull
Jessup (I'd have to commit to one of the two versions)
Jondalar
Karan
Parda
Phlydia
Piato
Reevor
Shank
Shistal
Theodon

Please note that for a full-fledged mod all 28 of the traditional NPCs would of course still be joinable as well.

But as I have been conceiving it, the mod would:

• Via patching replace the Candlekeep versions of the characters with my versions as joinable NPCs.
• Do away with the fetch-it quests and the assassination attempts before departing Candlekeep.
• IIRC the only characters from among the collection scripted to interact with the party are Theodon, Jessup, Bendalis, and Piato (in Chapter 6 of course). (Karan and Parda wouldn't spawn in the Prologue because the assassination attempts by Shank and Carbos are removed.) I would place those characters somewhere on the Candlekeep grounds in the Prologue; and in their locations within the library per the game if they are not selected as party members at the start. Those four monks would be scripted to respawn as joinable NPCs inside the library if they are not among the party members. And any of the joinable NPCs that weren't added to the party would still be there on the grounds, of course.
• The scripts that Bendalis and Piato have to speak with the party I would assign to other monks on the same floor.
• Remove the characters' dopplegangers in the eight side-rooms of the catacombs around the great hall where all the skeleton archers are. (I suppose I could replace them with the Chanter, the four Voices (of the cardinal directions), the two priests of Oghma, and the Gatewarden. But, really, those doppelganger encounters don't really add that much to the game imho. If only Winthrop, Gorion, Elminster, and Tethtoril appear down there as per the game that would be fine, I'd say... I would probably then relocate Winthrop to some place before Elminster, Gorion, and Tethtoril are encountered.

Now, it has been pointed out to me that it would be preferable to simply add the interactability as joinable NPC in order to avoid conflicts with other mods. And because a basic principle that many modders adhere with is to never change original content, only to add to it.

I dunno, though. Maybe this is heretical of me, but after the first playthrough I don't see the original content provided by each of these characters (although endearing) to be terribly significant to the game. I know that if I were to play with a mod like this, I would prefer to just replace the characters with the playable NPCs.

What are your thoughts about the sanctity of original content versus offering a more strongly modified version of the game that removes their original content?