I don't have a concrete solution for your problem, but instead of fighting with Emacs packages and customizations directly, I would *highly* recommend Spacemacs (http://spacemacs.org/).After using and customizing Emacs for several decades, I switched to Spacemacs some months ago and never looked back. Getting a coherent set of packages for a task, and getting those packages to actually work together requires a non-trivial amount of configuration fiddling. This is what Spacemacs does for you, plus an easy way to update.

Having said that, Spacemacs' Haskell layer works perfectly for me, perhaps you can give it a try. Another hint: Use stack/stackage instead of fiddling around with GHC installations, Cabal, sandboxes etc. for yourself.

Cheers,

   S.