I see no problem with the synopses.

The Xon did evolve into fair amount of intelligence. There are a
very few land masses on Centauri Prime, separated by huge oceans. The
two species evolved pretty much separately, on different continents that
were absolutely unreachable until one or both sides developed sufficient
technology for extended sea travel...and that's when all hell broke
loose.

Psi ratings vary a little, but not much; a P5 can be made into a P6,
but not much more. Generally, what you are is what you are.

(Many lower-level psi's, P1-P2s, are tracked by the Psi Corps, but
don't officially belong to it or function in any official capacity, as
their skills are *so* minimal or erratic as to be of virtually no real
use. Still, they have to be tracked and logged for genetic purposes.)

With only one exception, you won't see time travel anywhere in the
five-year run of the B5 story.

jms

The number of psi's in each category, from 1-12, gets rarer as you
get higher. Lots of folks have a minimal tendency, very few have any
real talent.

jms