Gameplay wise I think they are far too different, you'd kinda just have to pick one gameplay style over the other to make it work... but you bring up some interesting similarities with their settings. Dreams and whatnot.
Overall though I suppose nothing is impossible, there is always a way to make it work (like merging both gameplay styles into a brand new one), though I can't remember the last time I saw two obscure game IPs like Klonoa or Nights cross over with each other. That would be interesting to look into.