RE: Council votes. The big five powers (Earth Alliance, Minbari Federation, Centauri Republic, Narn Regime & Vorlon Empire) each get a vote because, well, they're the most powerful governments in the galaxy and they helped bank-roll the Babylon Project.
If it seems a little unfair or unbalanced it's probably because it is. Keep in mind though, that all the governments on B5 signed off on this system, mostly because just being there gives them orders of magnitude more influence, more say in galactic affairs and more trade opportunities then they'd have on their own. Without B5 they'd have to go on depending on foreign embassies and diplomatic missions to dozens of alien homeworlds, which few could ever afford to maintain.
The League of Non-Aligned Worlds is made up of fairly minor powers; some (like the Drazi) are bigger than others, but most only have a handful of colonies, not much in the way of military strength or economic influence. Basically they're the galactic equivalent of third world countries. The league's membership isn't even very stable as the smaller governments are prone to border disputes, shifting alliances and political spats. Not the kind of bodies that can be trusted with a vote or veto of their own.
Oh and yeah, the Vorlons more or less do as they please. A lot of this was established in the pilot movie, but basically of all the major governments, they're by far the most reclusive and secretive. Very little is know about them. Biology, motivations, society, technology: all complete blanks. Nobody has ever seen one of them outside of their encounter suits, no one has ever been to their homeworld and no ship has ever entered their territory (which is *huge*) and returned. All that the other races know is that they're powerful, very secretive and that they don't take much interest in the affairs of other races. That they agreed to send an Ambassador to B5 at all was a bit of a coup. Indeed, it's set up pretty early that they're one of the *big* mysteries of the show and I look forward to seeing you have it unfold for the first time.
The "suited ambassador" is called Kosh.
I think you are touching on some interesting things, and I think you will be very happy to know that all of your questions have answers.
I'm glad my questions have answers. As for Kosh, I should have remembered his name, or atleast googled it, but I'm sure it will stick with me eventually. It usually takes me a few episodes to remember a characters name, so I'll probably have his remembered soon
Some friendly advice: under no circumstances should you look up Kosh, or indeed anything do do with the show. There are *massive* spoilers out there and I'd hate for anyone to have the surprise(s) spoilt for them.