AH, a fellow fighter/melee combat enjoyer 🤝 I don't multiclass as much because I enjoy seeing what the classes have to offer in full and making them compliment each other with their respective restrictions, but I can respect it!
In my very first run I didn't touch anyone's class or subclass. I didn't even change their stats since I didn't know enough about DnD at the time to allocate them properly. Yes, It did make the game much harder on myself than it had to be 😂
For my consecutive runs I checked build guides and had help both online and from friends to better understand what the hell I was doing, so I would consider the following to be the "canonical" classes for my main party in DU drow's universe:
DU Drow- As most probably know, he is a Fighter. The subclass is less important since I change from Champion to Battlemaster depending on my mood, but flavourwise "Champion" probably suits him best. Hitting super damn hard and being able to tank damage for the rest of the team are the focus of his build.
Shadowheart- Tempest Cleric! I love the reactions/passives and the Tempest subclass still suits her story pre and post Shar the way I see it. She also tends to have some of the highest AC thanks to the heavy armor proficiency. I've done Light subclass as well (really good) and multiclassed her with Fighter, but I like her best as a pure cleric - and the Light subclass is a little too Selunite-y, which isn't necessarily how I envisioned her story going despite having turned away from Shar in DU drow's campaign.
Astarion- Rogue is my favorite class to play, and so anything besides Trickster for a subclass works for me. Flavor-wise, I like a Thief Rogue/Battlemaster Fighter multiclass best and center his build around dual wielding swords and hand crossbows. His build is a true Glass-canon, which works great since DU drow is usually soaking up most of the damage.
Gale- First of all, let me make it clear that I am really bad at wizards and resource-heavy classes (as you can probably tell from the builds above) so my Gale isn't as refined 😅 I find that I have the most fun with Evocation for a subclass and pulling Cloud of (insert element here) + Wall of (insert element here) shenanigans to either lock or direct enemies into damage. I find that this is the build that most suits Gale as I saw him and sates my thirst for overly-aggressive combat. That said, I have also had a lot of fun with the 1 Storm Sorc+11 Abjuration wizard build that deals damage back upon being attacked.
I don't rotate party members a lot so my builds for everyone else are nowhere near as exact (if you saw my HM streams you probably noticed how much I fumbled the bag with pretty much every other class that wasn't one of the above).
-While Wild Heart Barb is probably best, Karlach will always be a berserker to me. Unfortunately I do not find Barbarians very fun and they can often feel like a less-powerful fighter to me.
-I have a complicated relationship with Warlocks. On one hand, I feel like the class allows for some of the funniest strats - on the other, they are so resource heavy and feel so weak at early levels that I rarely ever use them. Devil-sighted Wyll can pull some great Hunger Of Hadar + Elright Blast shenanigans every seventh fight but the constant long-resting drives me up the wall. I don't even remember what Subclass I like best 💀
-Laezel (whenever she's alive) is made into a Battlemaster Fighter and functions similarly to DU drow in combat.
I have near zero experience playing with Jaheira or Minthara in my party, and Halsin must have survived 1 of my playthroughs at most, so I don't have any builds to offer for them - Moon druids are a little tricky but they're fun though, based on the little experience I do have! The Essentially Extra Health Bars go a long way 😂
BONUS - Ascended Astarion is a Thief Rogue/Open Hand Monk and you cannot change my mind.