I'll have to be a little circumspect here (damn it, you're doing it
again....). The Narn Regime is not currently at war with the Centauri
Republic, which occuped the Narn homeworld for nearly a century before finally
being driven off by the Narn resistance. Their resources depleted they are
not currently in a position to make war on anyone; being naturally rather
paranoid, and having just been more or less enslaved, they have a dread of
other races getting together and possibly harming them, as well as a hunger
for the technology that might protect them down the road (as Russia feared
invasion its Eastern Front after WW2).
There's a rough alliance between the Earth Alliance and the Centauri,
since theirs was the first race we encountered. (They told us at that time
that they were the biggest guys around, that they ran everything, that we were
a lost colony of theirs...which eventually was disproven by genetic
examination. The rest of their claims were also BS. They were trying to
impress the natives.)
There's some movement toward making nice with the Minbari, but also a
GREAT deal of resistance, given the recent war.
Here's one little extra for you: only one person aboard Babylon 5 has any
idea of what a Vorlon is, inside that suit, and only one race has had dealings
with the Vorlons before. Watch the reception at the end, and see if you
notice anything unusual in the way the various people respond to Kosh.