What party is everyone currently running?

My second run, I'm just using 3 hirelings from Withers so I can have 4 monks representing the 4 elements. And then I also dyed their robes red, blue, purple and orange so we are the Ninja Turtles.
- frantically taking notes

Wait I definitely didn't realize you could reclass the origin characters
- Yep! I'm trying to keep with each of their personalities or whatever, but you defo can. Just talk to Whithers as them.
  
  Mind... Blown. I like Gale, but I'm the damn wizard.

Karlach/barbarian
Shadowheart/cleric
Gale/wizard
Asterion/rogue
...in summary, the defaults. I wanna hear their stories :3

Half elf Order of the Ancients paladin
Shadowheart light domain cleric
Karlach beast ranger
Wyll champion fighter
I wanted Karlach in the party, but I didn't feel like I had room for her at the time as a barbarian. Booted Astarion and made Karlach a ranger so that I could still have rogue-like utility. Rogue or bard didn't make sense for Karlach lore-wise. Made Wyll a fighter because it turned out that I could have another melee fighter, and I simply cannot figure out a way to make warlocks as combat-effective as the other classes. And I don't like the absence of a proper spellbook anyway. But I like his personality. I chose paladin half-elf for the player character because there isn't a good-aligned paladin option otherwise, and half-elves get a +2 charisma racial bonus and fey ancestry.
At this point, I could probably restore Karlach as a barbarian and make Wyll a ranger. I like rangers because of the tactical options provided by pets. Particularly birds, because of how few enemy types are immune or resistant to being blinded. Plus, birds can cover ground quickly by flying, without using up an action. It's effectively a teleport that you can use every round.
Playing without a pure offensive caster seemed crazy at first, but it's going all right on the standard difficulty. Shadowheart's light domain spells fill in a surprising number of gaps -- and they are particularly effective in Act 2, which is where I'm at now.
The nice thing is, if I change my mind, reclassing is pretty inexpensive. Unlike many other games of this type, the price does not scale with the number of times you do it, or with character level, or anything else. It's always 100 gold.
- It doesn't feel, uh, heretical to have Shadowheart in the Light domain?
  
  I did the same thing as them. Yeah it’s goofy but I really wasn’t into the trickster domain and light is a lot of fun to play.
- Warlocks can be incredible for offense: eldritch blast + agonizing and repelling blast invocations with high charisma is a lot of at-will damage. Pact of the blade lets you ignore physical stats and be in melee with any weapon. fiend patron is great as it gives you temp hp on every kill and access to fireball. My MC is a full warlock and consistently kills half the things in a fight. Repelling blast in particular is incredible if you keep an eye out for enemies near ledges. With good positioning you can be booping two enemies to death per action.

My party is level 4.
Cleric of Talos (the chaotic evil god of storm and destruction), Tempest domain (obviously)
Shadowheart, default class (we're the couple of doom!)
Asterion, default class, subclass assassin
Gale, default class, subclass school of necromancy
Not like I have a choice, anyway, we killed all other companions (except Wyll, who left by himself before it happened). They started it!

I'm really enjoying this setup:
Custom Asmodeus Paladin - Oathbreaker (does a bit of everything)
Karlach Barbarian - Wildheart (Frontline)
Shadowheart Cleric - Trickery Domain (Support)
Astarion Rogue - Thief (Stealth Archer)
My typical strategy is for Karlach and my character to storm in and do a bunch of damage up close, while Astarion sneaks around for stealth attacks, and Shadowheart handles the buffs and whatnot (aided by my character, who also has Eldritch Blast).
Working really well so far! Plus, my character can speak with the dead and handle speech checks, Karlach can speak to animals, Astarion can pick locks, and Shadowheart helps out with rolls as well (I can't remember what that is called at the moment). So lots of bases are covered outside of combat!
- Are you me? That's literally my exact setup, only with a Mephistopheles Tiefling because I initially started as a Warlock.

I swap party members in and out a lot, mostly for story reasons, but here is how I built them:
MC: Ancients Paladin 7/Swords Bard 5 - Polearm Master, Sentinel - Lockdown Tank/Support
Karlach: Wolf Wildheart Barbarian 8/Thief Rogue 4 - Great Weapon Master, Tavern Brawler - Heavy Weapon Beatdown, Advantage Generator, Skill Monkey - MVP build
Astarion: Thief Rogue 3/Swords Bard 7 - Sharpshooter - Skill Monkey, Machinegun - MVP build
Gale: Conjuration Wizard 12 - Utility, Control, Haste-bot
Lae'zel: Eldritch Knight Fighter 11/Rogue 1 - Tavern Brawler, Sentinel - Gith Dragoon - MVP build
Shadowheart: Light Cleric 11/Druid 1 - Blaster, Support
Wyll: Fiend Warlock 6/Vengence Paladin 6 - SMITE
Halsin: Moon Druid 10/Monk 2 - Wildshape Tank
Jaheira: Land Druid 12 - Blaster, Control
Minsc: Gloomstalker Ranger 4/Bear Wildheart Barbarian 8 - Tavern Brawler - Improvised Weapons Control Tank

Dark Urge Monk Hexblade will Wild magic barbarian karlach Trickster cleric shadowheart
I run trickster for shadowheart because mirror image divine shield is stupid good.

Custom Drow Wild Magic Sorcerer
Shadowheart (Trickery Cleric)
Karlach (Berserker Barbarian)
Astarion (Arcane Trickster Rogue)
I'm finding that four party members is too few for my liking. Benching Astarion means having to go back to camp for him every time I encounter locks or traps, which is too annoying to bother with, and Shadowheart is always needed for Bless in combat and Guidance on checks (I provide my own Enhance Ability). That means I really only have one flex slot, since I can't bench myself, and it needs to be a front liner since I'm not one.
The previous two BG games had six person parties, which was way better. I would like to be able to bring Lae'zel as a second front liner, and Gale because he knows all the utility spells.
- I don't know if you want to use mods or not, but I'm pretty sure I saw an increase party size mod on nexusmods the other day
  
  I found one but it says it might break things, so I'm waiting for one that's more stable. Also ideally you'd rebalance encounters around the increased party size, but that would be a massive undertaking so I don't expect a mod to ever do it.
- I definitely agree in wanting a bigger party size. 5e is pretty optimized around 5 person parties. 6 is a bit harder to balance around, but still doable.

Are there any negative consequences for respeccing the origin characters? (barbarian Gale, etc)
- Just the 100g cost as far as I can tell. Sometimes it might make story beats weird, like if a character naturally is a warlock, their patron might show up even if you changed them to fighter.

Running a vanilla group. Nothing fancy.
Bard, barbarian, fighter, cleric.
It's got smashy smashy, some heals, and a groovy beat.
Oh, and the bard is wearing Minthara’s underwear. 😆

MC Tav Gith warlock 9:
fiend+blade pact for up close
eldritch blast + agonizing + repelling for ledge boops and while closing gaps
gith for medium armor and the totally bonkers ancestral knowledge. I have proficiency in effectively all skills, and charisma for winning dialogue
using sorrow for reliable bonus action attack+yank
Shadowheart trickery cleric 9
“you cast guidance”
spirit guardians, guardian of faith, and spiritual weapon can all be going at the same time
a magic bow that causes the frightened condition is the cherry on top.
Karlach paladin 6/barbarian 3
you can smite while raging
those couple extra free racial smites are nice
currently ancients + berserker, but planning to switch to wild magic
using blood of lathander
Gale evocation wizard 9
“I didn’t ask how big the room was, I said I cast fireball”
- Hang on you can smite using racial spell slots? WotC please take note.
  
  I think Tieflings get searing smite and branding smite as racial skills that can be used once per long rest. They cost an action and are definitely a nice to have as a Tiefling Paladin MC

Can you spoiler tag your late game companions please! Just spoiled myself!

Currently :
MC deep gnome warlock2/bard7
Karlach 9 battlemaster
Wyll 6battlemaster 3assa rogue (ranged bow)
SH 9 light cleric

I have... problems long resting as much as the game wants me to. Long rest classes give me stress. Also I don't really optimize builds much, but
main character half elf fey warlock, pact of the chain
wyll as pact of the blade
laezel as 23 ac battlemaster sword and board. She's basically indestructible. Heavy armor master + adamantine armor means she can't be crit, and damage is reduced by 5.
shadow heart as her default cleric, but honestly she's not pulling her weight a lot of the time. Spirit weapon is nice but misses a lot and has butt for movement speed. Spirit guardians is real nice, admittedly. Cleric cantrips kind of suck.
On the other hand, two warlocks with devil's sight and gith lady with an "immune to blind" ring is extremely effective. Shadow heart can chill out in the dark with spirit guardians, too.
Only in act 2 though we'll see how the rest of the game goes!
- If you want to focus on short rests you should pick up a bard. Song of Rest effectively gives you an additional short rest per long rest.