I just downloaded your replays, Ildarik, and I'll be studying them. Actually, in this matchup, I've only played as Axel before and just cast spells. An average Heroes of Might and Magic player will never cast plague for Deirdre:)
The Sinith - Helm pair: for some reason, I always had good luck, either with spells or with mana economy, Sinith rarely lost. Maybe I just didn't encounter strong opponents.
Another replay: Garuna defeats Helmar (although this was mentioned earlier in this thread, but there were no replays).
Against Anwen, Ibbe should be positioned on two squares (like Iris), I think. Although that might not save you.