Vitali is one of the greatest heavyweights in history and his skills and chin are matched by a tiny few. Fury would be outjabbed and beaten up with ease.
Vitali will never return, but if he did he would face Wilder as of now, as he is the WBC emeritus champ and would fight whoever is the WBC title holder at the time of his comeback.
If he had a good training camp, which he wouldn't now as his long-term sole trainer Sdunek died, and injury-free, he would probably still beat the majority of heavies out there, but that's not going to happen so no point really thinking about it.