I went through all of the languages you mention, and OCaml/ReasonML are what you're looking for (if you want a typed FP language). More than 50% of FB messenger is written in ReasonML so it's clearly a good long term investment. If you don't like the ReasonML syntax, then you can just use OCaml because they're 100% interoperable. It's also a very practical language, which unlike the others doesn't militantly enforce purity, and lets you directly write imperative code.