off the top of my head, Dual Wielder with Lae'zel has been cool. Two weapon fighting with long swords and +1 AC is good. That one also works for a barbarian or a strength based ranger. Though not used as much, armor proficiency feats are also nice, and will be nicer when they give us better armor to work with in the future. Once they give us full plate armor, I will probably have Shadow heart Take the heavy armor proficiency, so she can use full plate. I sometimes have liked to give Gale light armor proficiency, just because he's such a wuss. I've also given Wyll better armored class proficiency as well, because he's so squishy.
Those are certainly interesting choices ...
A few questions if you please.
There is no overstatement my interest!

Dual Wielder for Lae'zel, dont you feel like you are wasting it a little?
Since she starts with
Great Weapon Fighting style by default. O_o
To me it seems she would work much better with
Great Weapon Master Feat ... of course especialy after they fix that Bonus Action attack ... wich as i heard (didnt try myself) dont do anything right now.

(It would be kinda half-wasted on Berserker Barbarian tho, since they allready are attacking with their Bonus Action, when they Rage ... i mean Frenzy

)
But IF we would have option to diceroll our stats, this could unlock its true potential ... i mean -5 is heavy penalisation, if your character have only +3 from 17 Strength.

Giving plate armor to Shadowheart seems also a little odd to me, since then her 14 Dex would be completely wasted. :-/
Is that really worthy that +1AC, when compared to Half Plate he can wear right now ? O_o
Also i wonder wich armor did you find for gale, so it was better than 13+Dex he have from Mage Armor. O_o