«grey» instead of «gray» is not accepted, it should!
Could you say Con voi là màu xám? Is there a difference in how 'is' is used?
Why "The grey elephant" is not accepted?
Because that would be "con voi xám"
Because there is a verb (có), so you need to translate this as a sentence.
Because that's not what it says
the elefant 'has' a grey color...