In the second game, why the Zentharim insist on trying to whale on your character (who has proven to be a though obstacle) rather than going for the other members of the Harpists like Randalla or Jherek?
Possibly because your character is implied to be several, possibly even all five of the main choices - some of the dialog shows that there are multiple characters there doing things, even though the player only sees one.
Furthermore, both Randalla and Jherek are hid safely inside Baldur's Gate, where it could be difficult to attack them at once with many soldiers. On the other hand the hero/es are out in the wildlands, where an accident can happen and noone can help them out.
Ok, nearly all the monsters you meet can be recognized as the ones from the Monster's Manual but... what are exactly those monsters clad in red armor in the Hammer Halls? The ones with enchanted swords and crossbows?
Animated objects, perhaps? Animate Objects can be just about anything, so a clever DM could totally throw animate suits of armor wielding weapons at a party. We apologize for any Total Party Kill you may suffer because of this.