I've always though Odo more a lawful neutral type. He never seemed to really care who was writing the law, only who was breaking it. He upheld Cardassian and Dominion law just the same as Federation or Bajoran.
O'brien had some borderline racist baggage regarding Cardassians. Chaotic good fits him well. I'd say aside from Picard, chaotic good fits most of the major Starfleet characters in the shows - many of them favor getting the right things done the most important thing, and the rules rarely stop them from doing that.
Bashir's very existence is a crime, and the fact that he's still in Starfleet is the result of authorities choosing to look the other way on the matter. And in TNG we saw that the Federation takes its laws on genetic engineering and cloning seriously enough to justify killing a defenseless sentient in cold blood and dismantle a peaceful society, and we even saw several others like him who had been incarcerated for life, so this isn't a trivial thing to look the other way on. I wouldn't call him outright criminal, but he's got enough baggage to lock him out of the lawful end of the spectrum. I'd say neutral good to true neutral, which suits being a healer well.