Is it just me, or did Sheridan do EVERYTHING that was in his power to START a war, not to prevent it?

It ain't just you.

What should he have done differently?

Is it me, or does the harsh conditions on the Centauri seem to mirror the Treaty of Versailles?

yes, JMS has always been a big fan of history. In the book series that tells the story of what happens to the Centari after the series an evil dictator takes power, bars all other races from the planet, controls the people through fear of outsiders and created a millitary dictatorship intent on starting a new Centari Empire through conquest.

Oh I've read the Centauri trilogy, and it was indeed an excellent piece of work, and I can again see some parallels to post WWI Germany, with the Centauri youth organisation (Can't remember the name).

They were called the Prime Candidates. And Welch makes a crack about their resemblance to the Hitler Youth.