Sisko mentioned the Fire Caves way back in season 1 ("The Nagus"). I like long-term story continuity like that.
It does make you wonder why the Prophets would have put their enemies in some caves on Bajor. I mean, apparently these pah-wraiths can get out pretty easy, if one took over Keiko. Makes you wonder how many others have escaped over the years and reeked havoc on Bajor. I thought the Prophets cared about the Bajorans. Why would they put their enemies on Bajor? Maybe they had nowhere else to put them? The Prophets' influence does seem to be limited to the Bajoran system. (We only see their influence anywhere else when Sisko discovers the Orb of the Emissary on Tyree.) But you'd think there's a random moon or something they could have used.
Apparently Odo's humanoid body has a glass jaw. I mean, he got knocked out by a single punch from an engineer.
I like it when we seen birthdays mentioned on Star Trek. It makes the characters seem more real.