Try Elven names from the silmarilian for the Minbari. I'm sure JMS has tried to slip one or two in, but I don't pay attention to that.
as for the Narn, try gutteral sounds, for example.
Bra'Tak
Gor'Don
Ghaz'Hor
or even shortening some words to one letter and one or two syllables like Murder becomes M'Dur (but pick some words that sound good, and you'll know when you have a good sound)
Coincidently, this works with some names (Shakieria become Sh'Kieria, for example)
It may even be worthwhile to look at some of the Germanic lanuages for inspiration