You can defeat all the heroes of the Stronghold with Sinithar (one on one, that is)! He's great in duels against Dungeon!
And Ossir and Anwen can defeat all three heroes of the Sylvan!
By the way, I played Ultimate with Prizrak, Dungeon vs. Orcs! He beat me. Letos against Goshak! The moral: it's not advantageous to play Dungeon against the Stronghold in Ultimate, but a rush for Vayshana is a death sentence! Proven! And dueling Orcs... ugh, they're very weak!