Thank you for doing this, great news indeed!
Having never played NPC mods extensively, I can't really give feedback on them.
In regards to Drizzt:
I've pictured him along the lines of how artastrophe has imagined Soulafein - frontal gaze, focus on eyes, kindly yet badass expression.
Distinctive features: Drizzt has deep lavender eyes as well as his green cloak.
Reference art: portrayal of Drizzt by Todd Lockwood: http://toddlockwood....dourden/drizzt/ (there are more images in the album).
Other ideas to consider:
Wilson the bear - hidden NPC from BG2:EE, while not as deep in character as his more humanoid counterparts, it would be nice to have Wilson be re-imagined, at very least for "art for all NPCs" completion sake.
Baldur's Gate: Siege of Dragonspear NPCs (Can be found at http://www.siegeofdragonspear.com/)
Plot NPCs: Gorion, Thalantyr, Elminster, Volo and other (there are some mods that add portraits to these characters, but they look dated and it would be nice to have them of the same style as PaintBG NPCs)