Yes, the min and rec specs for Mortal Empires will be the same as Warhammer II. Is it the same min/rec spec as WARHAMMER II? Mortal Empires is a free downloadable content pack that you can access from Total War: WARHAMMER II’s DLC list on Steam.
It enables players to embark on new campaigns as any playable Legendary Lord they own from both games and any owned DLC. Mortal Empires is a grand-scale downloadable campaign set across a massive new campaign map, free for owners of both Total War: WARHAMMER and Total War: WARHAMMER II.