"There is dust in the house."
Translation:Υπάρχει σκόνη στο σπίτι.
I know υπάρχει σκόνη στο σπίτι is more correct, but is είναι σκόνη στο σπίτι completely wrong?
I can't find this sentence, which means it's been either changed or deleted, but to answer your question, "Το σπίτι έχει σκόνη" wouldn't be wrong. ^.^ (it's just not a direct translation, but this case, I guess the meaning of the sentence would remain the same.)
Yes, six. (Though one of them is extremely rare, so five ways for all practical purposes.)
English has lots of ways to write that sound as well, though -- seen, lean, mien, scene, ..