To answer your questions in detail would be to give out major plot
points from the B5 series, and I'm loathe to do that. Thus, I'll only
answer some of the questions, and in no more than one sentence each.

Yes, a psi can go undetected, but generally not forever. Some say
the Psi Cops are witch-hunters, some think otherwise. Breeding is
generally arranged. It is possible to have a schizoid telepath. The
Psi Cops can function as lie detectors. Psi Cops are telepaths, rated

P12, the highest level admitted level of telepath. They are part of
a guild, with some government regulation, though that's fuzzy. They do
not have the same rights as other citizens -- most have fewer rights than
other citizens, a few have more -- and the different races handle their
telepaths in different ways.

jms