Trying to figure out a 4th

Hello im getting ready to start a new playthrough and have nailed down three out of four of my builds. This will be my seventh or so playthrough so I'm not too worried about min max builds but more so thematic fitting and unique ones. This will be a mostly good playthrough for what its worth but one of my Tavs will be a Dark Urge that resists. Ill give you what I've got so far and if you have any suggestions id love to hear them!

Tav 1: Elemental Spellsword- This character is a EK Fighter and Thief Rogue multiclass that focuses on using mostly cantrips and low level offensive elemental cantrips to buff up there weapons to then use their two bonus actions to swing with the offhand. Should have a good balance between offense and defense.

Tav 2: Fey Touched Sorcerer- This character is a fairly standard Archfey Warlock and Wild Magic Sorcerer multiclass getting most of its damage from EB and then its spells focus mostly on control with ones such as Slow, Hold Person, Charm, Etc. This should be the character that the majority of my CC comes from ideally.

Karlach: The Raging Goliath- The pretty standard Wild Magic Barbarian that wants to get in there take a bunch of damage and hit stuff hard. Will be using the Baulduran Great Sword eventually. Main tank of the group.

Spot 4:???- Im leaning towards Shadowheart cause Shadowheart so bonus points if the build fits her but im open to anything. The two I've been looking at the most have been a Holy Archer type build that uses the Luminous Armor and the Gontr Mael to stack Radiant Orbs or some type of dual wielding dagger assassin as I've never really tried that playstyle out before.

Cant wait to read any suggestions and thanks ahead of time!