Mel will try to resurrect Jon and fail. Jon will rise again as a wight when the Night's King blows the horn that wakes the sleepers. No Jon... just a frozen meat bag with Jon's face.
That's similar to the prediction I made over on the Show Predictions thread. I hadn't read this yet and I guess our brains went to similar places on this. Yours is more explicit than mine. I just said the Cold will raise him and Mel will get the Cold blue of the wights out of him. And in turn, reveal that she's a wight too, but raised and sustained by the Lord of Light.