I just completed it, Conq's strategy in starting from the left was super helpful to me. Although, instead of taking out the cleric, I took off the Solar Brace from LEphraim and stood right in front of the Blue Lance to tank a hit from that (and counterkill) and the Cleric to drop me to half health. Xander moves forward, as did the Gronnwolf, but the Green Mage went right for some reason. I only had an Olwen, but a Swordbreaker helped me ORKO Xander, after which I WoM'd the Gronnwolf with Siegbert (I was expecting the green mage to go left, which is why I had WoM on Siegbert and took off the Solar Brace in the first place, but it went right so strictly speaking I didn't really need to do all that I guess). I heal up Olwen back into Swordbreaker range with Elise and had her tank a hit from the Red Sword, who died next turn from Olwen. Siegbert kills the Green Mage, and I heal L'Ephraim to survive one more round vs the Cleric, then go up and kill her next turn.
LEphraim had Ward, Bonfire and Distant Defense, Elise had Hone, and Siegbert had Fortify Horses.