Thanks for clearing that up.Denethor is one of the Green Elves, the Laiquendi. The Falathrim are not in this.
The parallel between Denethor-of-the-Green-Elves and Denethor-Steward-of-Gondor will be a quotation that will be put into the mouths of both of them. Denethor, in this battle, will say something like, 'Now would be a really good time for the dwarves to show up!' (sometime after the fighting starts, but before he dies). Denethor-the-Steward will make a similar comment about the Rohirrim prior to the Battle of Pelennor Fields.