. . .
The Lankhmar line really needs to take the same approach taken for Elric and Hawkmoon:
1- MAKE THEM UP! Take every cool hint found in the source material and run with it making up cool stuff consistent with the mood of the story.
The stories hint at many things that are not described: Earth magic of the Kleshite priests? Frost rituals of the northern women? Necromancies from Quarmall? Deep rituals of the Symorgians? Black ice magic of Kakht? The aerial elemental realm of princess Frix? MAKE THEM UP!
2- STAT 'EM UP! I mean all those NPCs from the stories!!! And also generic NPC types: thieves, priests, beggars, nobles, whores, merchants, thugs and assassin, northerners, land Mingols horsemen, sea Mingol pirates, etc.