Dwarf gourami are just plain hard to keep alive, and will also eat tiny fish. Most any fish will eat tiny fry. Cories maybe less likely to, simply because they forage more on the bottom but they're quite capable of swimming to the top when they want to. Fry do best kept separate until they are big enough to cope on their own.
Mosquito fish are becoming invasive in many areas.. having been handed out willy nilly to control skeeters in ponds, without considering they can adapt to native waters quite well.