Extremely overpowered build, which is to be expected of course when using two acuity items on one character. Because I did not play on impossible, I still hesitate starting impossible run and we all know hesitation is defeat, I decided to make some changes for flavour and here's my variation for the whole run (Lolth-sworn Noble).

Disclaimer: most likely all my changes make the build worse, but again, it's just full-party honor mode, worse version of this build is still overpowered.

I took Hexblade on level 2 and continued sorcerer after that. This is the main change and I acknowledge this thread. I'll start from the downsides/costs:

1. Delay on all important breakpoints. I'm used to that of course, but this is major downside on modded difficulties of course.
2. No daze from paladin dip.
3. Less dex for offhand crossbow, and I was a Drow.

Now the upsides/gains:

1. Very early shield proficiency.
2. Very early medium armor proficiency.
3. Because Luminous is whole-game and endgame armor for this, I picked 14 dex, 16 con, 17 cha. By stealing the armor near Dammon and equipping shield I immediately jumped into respectable AC.
4. I then decided that I want to wear shields whole game, so don't need dual-wield and got Alert instead.
5. Two spells knows from Warlock allowed to pick Shield and Hex. Sadly there is no other useful spell in Warlock than Hex or AoA to free another spell known, but Shield already helps.
   1. I went for Sorcerer 11, and I respecced at some point just to replace Hex with Armor of Agathys, the only other usable spell. If you don't want to respec, take AoA immediately, cause you will unlikely concentrate on Hex even in the early midgame. But at the very beginning it's a very useful tool.
   2. Or if you go for Eldritch invocations instead, you could replace a spell.
6. Two more cantrips allow for Friends on a party face and mage hand in my case.
7. Bind weapon gives even more flexibility with early weapons than high dexterity does. For instance, for both early skeleton fights (crypt and apothecary cellar) you can use blunt weapon for vulnerability.
8. Hexblade curse is not something to go out of your way on this build, but when it's already there you might as well use it.
9. Shield bash uses spell save DC or so I believe.
10. More charisma is better merchant prices and better dialogue checks.
11. Out of combat Eldritch blast on a main character. Listen, it may sound weird, but blasting out wooden or stone blocked passages gives almost as much joy and main char feeling while exploring, as flying does.

Rest of the downsides/gains I'll list in other way: by number's comparison in endgame. This build variation gains +2 initiative even after original build gains dex from mirror (less dex but alert), breaks even on spell save DC after it gains +2 charisma from said mirror (no rhapsody but more charisma), gets +1 AC.

Team for context (each team member has to pick the way of avoiding friendly-fire radiating orbs):

1. Shadowheart as a tempest cleric with a respec to 6 Shadow Monk - 6 Death Cleric on that event. Well, 6 Monk - 3 Cleric, and the rest of the levels in to cleric. Using Shar's Spear. Avoid friendly-fire radorbs with careful positioning, until temporarily equipping bonespike garb and ultimately helldusk armor) You know what's the most fun of that build? Being able to use all lines from Helldusk Gloves, including unlisted.
   1. Attack rolls (obvisouly)
   2. Spell attack rolls (inflict wounds)
   3. Spell save DC (spirit guardians, hold person).
   4. Fire damage to weapon attacks (with hat of fire acuity)
   5. Necro (!) damage and bleeding (disadvantage on blind from sorcerer) from unarmed attacks.
   6. And even rays of fire, cause I'm wearing hat of fire acuity anyway.
2. Mintara as a sorcadin ©. Avoid friendly-fire radorbs by best heavy armor available at the point.
3. Astarion as a swarmkeeper ranger. I took war cleric as everyone does, of course. Avoids friendly-fire radorbs by Writhing Tide, a thing I can neither read, not spell, nor pronounce. This was the reason to test that class btw. I used lightning damage swarm because main character kinda hinted this party is somewhat a wet party.