Dirael is no match for Jallib, it's almost impossible to win with Dirael, even if luck is on your side. You just need to gather the mages in one group and put a shield on them. In this way, Jallib wins against almost all mages, except for Helmar, and it can be interesting against Marbas.
Sinithar vs. Deidra. With Deidra, a few vampires with vampirism should be enough to win, I don't see a problem, except for luck. In general, without luck, Sinithar gets crushed by almost everyone.