What's the actual problem? Company decided to use Haskell (which is also a general-purpose language) then hired people who don't know it?
If so, hire a bunch of Pythonistas to work on a Rails project and you'll have similar kind of struggles (and it won't mean that Python or Ruby are somehow bad, it'll be an almost entirely non-technical issue).
again my point is about adoption, hence offering multiple languages in most products like stripe for ex
edit: it's alright, when they actually ship these things (after putting down $3.5K) I hope I will take it upon myself to port it to C++ myself
edit: "general purpose" is probably the wrong way to put it, Haskell is harder to read than C++ is my pov
Still... I'm working with someone who came from a Swift background and thinks JavaScript is hard so that goes against my thought.