>>534744649
>>534747770
Teclis has to deal with Kairos and Alith is like playing Eshin where you want to spam armies of skirmishers, so they're probably the worst first picks.
Tyrion is the "learning to play Helves" lord but since you find him too easy you probably won't find Alarielle engaging either.
That leaves Imrik and Eltharion. I'd go Imrik since Eltharion has more campaign mechanics and special units that aren't really representative of the base race, while Imrik just gets some unique dragons.