NPCs are generally ordered in the order in which you will find them in the game - but there are a few exceptions.
Listed characteristics of NPCs:

• Name, Sex, Alignment, Race & Class. (If ranger racial enemy is also listed)
• Statistics.
• Weapon Proficiencies.
• Starting Equipment.
• Special Abilities, if any.
• #  Tells if a NPC is paired with another. i.e. they will join and leave the party as a pair.
• ~  Tells of any quest that a NPC asks you to complete.  Also tells what will happen if the given quest is not completed within a certain time limit.
• Where they are found.
• Any other important information about the NPC.

Imoen Female Neutral Good Human Thief

Str	Dex	Con	Int	Wis	Cha
9	18	16	17	11	16

Weapon Proficiences: + Small Sword, + Bow.
Starting Equipment: Short Bow, 20 Arrows(x2), Potion of Healing(x3), Potion of Speed, Wand of Magic Missiles.
Joins you at the start of chapter 1.
Can be dual classed to a mage. (Preferably a specialist; illusionist is a good choice)
 

Xzar Male Chaotic Evil Human Necromancer

Str	Dex	Con	Int	Wis	Cha
14	16	10	17	16	10

Weapon Proficiences: + Small Sword.
Starting Equipment: Dagger, Scrolls: Larloch's Minor Drain & Chill Touch.
# Paired with Montaron.
 
Montaron Male Neutral Evil Halfling Fighter/Thief

Str	Dex	Con	Int	Wis	Cha
16	17	15	12	13	9

Weapon Proficiences:  + + Small Sword, + + Missile Weapons.
Starting Equipment: Studded Leather Armor, Short Sword, Potion of Healing, Potion of Speed.
# Paired with Xzar.
~ Xzar & Montaron ask to go to Nashkel; will leave if not done.
Found along the road on the starting map.
 
 
Khalid Male Neutral Good Half-Elf Fighter

Str	Dex	Con	Int	Wis	Cha
15	16	17	12	10	9

Weapon Proficiences: + + Large Sword, + Bow, + Axe.
Starting Equipment: Splint Mail, Long Sword, Medium Shield, Helmet, Potion of Healing.
# Paired with Jaheira.
 
Jaheira Female True Neutral Half-Elf Fighter/Druid

Str	Dex	Con	Int	Wis	Cha
15	14	17	10	14	15

Weapon Proficiences: + + Blunt Weapons, + + Missile Weapons.
Starting Equipment: Leather Armor, Quarterstaff, Potion of Invisibility.
# Paired with Khalid.
~  Khalid & Jaheria ask to go to Nashkel; will complain if not done.
Found in the to the left of Bentley inside the Friendly Arm Inn.
 
 
Ajantis Male Lawful Good Human Paladin

Str	Dex	Con	Int	Wis	Cha
17	13	16	12	13	17

Weapon Proficiences: + + Large Sword, + Bow, + Blunt Weapons.
Starting Equipment: Chain Mail, Bastard Sword, Medium Shield, Helmet(Purple) with side feathers.
Special Abilities: (Standard Paladin Abilities: Lay on Hands, Detect Evil(x6), Protection From Evil(x2).
Found west of the south entry onto the area north of the Friendly Arm Inn.
 
 
Kagain Male Lawful Evil Dwarf Fighter

Str	Dex	Con	Int	Wis	Cha
16	12	20	15	11	8

Weapon Proficiences:  + + Axe, + Blunt Weapons, + Missile Weapons
Starting Equipment: Studded Leather Armor, Battle Axe, Medium Shield, Winged Bronze Helmet.
~ Will ask you to help him search for a caravan which had the son of Entar Silvershield.  After a while will say he can't be bothered; "Let's just forget about it and keep to whatever you want to do."
Found in the building north of Feldepost's Inn in Beregost.
Note that Kagain has a Constitution of 20 - which allows him to regenerate hit points!

 
Kivan Male Chaotic Good Human Ranger (Racial Enemy: Ogre)

Str	Dex	Con	Int	Wis	Cha
18/12	17	14	10	14	8

Weapon Proficiencies:  + + Bow, + + Spear.
Starting Equipment: Studded Leather Armor, Spear, Short Bow, 20 Arrows.
Found southwest of the east entry of High Hedge area.
 
 
Minsc Male Neutral Good Human Ranger (Racial Enemy:Gnoll)

Str	Dex	Con	Int	Wis	Cha
18/93	15	15	8	6	9

Weapon Proficiencies:  + + Large Sword, + Spiked Weapons, + Axe.
Starting Equipment:  Studded Leather Armor, Two-Handed Sword, *Boo.
Special Abilites:  Beserk.
For duration of Beserk state, Minsc gains 15hp, and gains +2 bonus to hit and damage, and you will lose control of Minsc whenever an enemy is in his vision, as he will continue to attack anything in sight.  Minsc may also attack members of your party - if this happens, run them away from Minsc and he should calm down after a short period.  Minsc loses 15hp at the end of his beserk state; this will kill him if he has less than 15hp.
~ Asks you to help him rescue Dynaheir; will attack party if not done.
# Will pair with Dynaheir once combined.
Found outside the barracks in Nashkel.

Dynaheir Female Lawful Good Human Invoker

Str	Dex	Con	Int	Wis	Cha
11	13	16	17	15	12

Weapon Proficiences: + Missile Weapons.
Starting Equipment: None.
~ Will ask party to search for Minsc if not already in party.  Unknown what happens if not done.
# Will pair with Minsc once combined.
Found in the second pit east of the first set of stairs north in the Gnoll Stronghold.
 
 
Edwin Male Lawful Evil Human Conjurer

Str	Dex	Con	Int	Wis	Cha
9	10	16	18	9	10

Weapon Proficiences: + Blunt Weapons.
Starting Equipment: Quarterstaff, *Edwin's Amulet.
~ Asks you to help him kill Dynaheir.  Will leave if not done.
Found on the bridge at the south of Nashkel.
 
 
Branwen Female True Neutral Human Cleric

Str	Dex	Con	Int	Wis	Cha
13	16	15	9	16	13

Weapon Proficiences: + Blunt Weapons, + Missile Weapons.
Starting Equipment: None
Special Abilites: Spiritual Hammer (x3)
Found as a statue at the Nashkel fair - requires a stone to flesh scroll to restore her before she can join.
 
 
Xan Male Lawful Neutral Elf Enchanter

Str	Dex	Con	Int	Wis	Cha
13	16	7	17	14	16

Weapon Proficiencies:
Starting Equipment: None - but in Mulahey's chest; Moonblade(only useable by Xan) & scrolls: Infravision, Identify, Charm Person, Sleep, Armor & Web(not useable by Xan).
Found at the bottom most level of the Nashkel mines, in the southeast chamber.
 
 
Shar-Teel Female Chaotic Evil Human Fighter

Str	Dex	Con	Int	Wis	Cha
18/58	17	9	14	7	11

Weapon Proficiencies: + + Large Sword, + + Small Sword.
Starting Equipment: Studded Leather Armor, Long Sword, Small Shield, Helmet.
Found in the northwest corner of the area east of the Temple at Beregost. A male must defeat her in a duel before she will join.
 
 
Safana Female Chaotic Neutral Human Thief

Str	Dex	Con	Int	Wis	Cha
13	17	10	16	9	17

Weapon Proficiencies: + Small Sword, + Missile Weapons.
Starting Equipment: Leather Armor, Dagger.
Special Abilities: Charm Animal.
~ Will ask you to help her find some treasure.(Which is in a cave on the map you find her - guarded by Sirines); Will leave if not done.
Found a little southwest of the centre of the Lighthouse map - second area south from Candlekeep or alternatively, southwest of High Hedge.
 
 
Coran Male Chaotic Good Elf Fighter/Thief

Str	Dex	Con	Int	Wis	Cha
14	20	12	14	9	16

Weapon Proficiences: + + Large Sword, + + + Bow.
Starting Equipment: Leather Armor, Long Bow, Long Sword, 20 Arrows.
~ Will ask you to help him kill a Wyvern in its lair; Will leave if not done.
Found on the bridge in the northwest corner of the first area of cloakwood.
 
 
Eldoth Male Neutral Evil Human Bard

Str	Dex	Con	Int	Wis	Cha
16	12	15	13	10	16

Weapon Proficiencies: + Small sword, + Missile Weapons.
Starting Equipment: Studded Leather Armor, Dagger.
Special Abilities: Create Poisoned Arrows.
Creates 5 poisoned arrows only useable by Eldoth.  The arrows have a poison that deals 1 damage periodically.
~ Requests that you help him 'rescue' Skie once in Baldur's Gate.
# Paired with Skie once combined.
 
 
Skie Female True Neutral Human Thief

Str	Dex	Con	Int	Wis	Cha
11	18	15	15	8	13

Weapon Proficiencies: + Small Sword, + Bow, + Missile Weapons.
Starting Equipment: Short Bow, 20 Arrows.
# Will pair with Eldoth when combined.
Can only join party through Eldoth. Found upstairs in the western end of Entar Silvershield's 'House'.
 
 
Faldorn Female True Neutral Human Druid

Str	Dex	Con	Int	Wis	Cha
12	15	11	10	16	15

Weapon Proficiencies: + Blunt Weapons, + Missile Weapons.
Starting Equipment: Leather Armor, Club.
Special Abilities: Summon Dread Wolf.
Will summon a dread wolf that can be commanded.  (Can be killed for 65 exp.)
~ Asks you to help her get rid of the Iron Throne mine in Cloakwood; Unknown what happens if not done.
 
 
Yeslick Male Lawful Good Dwarf Fighter/Cleric

Str	Dex	Con	Int	Wis	Cha
15	12	17	7	16	10

Weapon Proficiencies: + + Blunt Weapons, + + Missile Weapons.
Starting Equipment: None.
Special Abilities: Dispel Magic.
Found in the second level of the cloakwood mines.  You must find two secret doors - one off the northern most northwest-southeast corridor, and then one right and the end of the hallway that you enter off the first secret door.
 
 
Viconia Female Neutral Evil Elf(Drow) Cleric

Str	Dex	Con	Int	Wis	Cha
10	19	8	16	15	14

Weapon Proficiencies: + Blunt Weapons, + Missile Weapons.
Starting Equipment: Leather Armor, Mace, Small Shield.
Special Abilities: 50% Magic Resistance. Not a special ability as such - but should be noted nonetheless.
Found in the northwest corner of Peldvale.  You must kill the flaming fist mercenary to have her join your party.  When she first joins your party, you will lose two points of reputation.
 
 
Quayle Male Chaotic Neutral Gnome Cleric/Illusionist

Str	Dex	Con	Int	Wis	Cha
8	15	11	17	10	6

Weapon Proficiencies: + Spiked Weapons, + Missile Weapons
Starting Equipment: Sling, 20 Bullets, Flail.
Special Abilities: Invisibility.
Found just outside Baldur's Gate.
 
 
Tiax Male Chaotic Evil Dwarf Cleric/Thief

Str	Dex	Con	Int	Wis	Cha
9	16	16	10	13	9

Weapon Proficiencies: + Blunt Weapons, + Missile Weapons.
Starting Equipment: Leather Armor, Mace, Sling, 15 Bullets.
Special Abilities: Summon Ghast.
Will summon a Ghast that can be commanded. (Can be killed for 65 exp.)
Found just south of the Flaming Fist headquarters is Baldur's Gate.
I am quite sure that Tiax cannot backstab, as cleric weapons are not suitable for backstabbing.  If he can backstab, tell me how.