Of all the abolished Monarchies in Europe (including Russia) are any of them likely to be restored one day?

Very unlikely, If the EU have there way Europe will become a federal state with no place for monarchies, the only ex royals who have campaigned for a return of the monarchy is ex king Constantine of Greece and although he makes regular visits back to his homeland the people of Greece have made it clear to him and his family they do not want a return of a monarchy in Greece