Thanks for the Lordlake strategy, KFC. It gave me a good foundation for what to do. Still takes a little luck, but I got it done. Didn't even know about the Cyclone Piece there. Made it a bit harder. Here's how I approached it.
I gave Dinn and Boz's units 5/5 Charges, then formed the center of a wall in front of Lordlake. It's easier when you don't have to pay attention when to prompt an attack, like you do with Barrage, and instead can wait for the enemy to run into you, like with Charge. That allowed me to focus on other things when needed.
I then had Isato/Urda/Lu (5/5 Barrage) and Jeane/Killey/Shinro (2/2 Thunder & Rage) form the second tier north and south of Boz/Dinn, to give my wall ranged attacks. Then had Prince and Talgeyl form the outer tier of the wall just to be sure. These units never moved.
The enemy should funnel into Boz/Dinn. At which point, I just use Charge to repel them, then have Isato follow up with a Barrage to push them back further, taking some pressure off of Boz/Dinn's charge supply. With the Cavalry units being faster than Infantry units, I didn't have to pursue the Cape of Destiny. I just let it come to me, finishing the unit off with Thunder or Barrage when it was weak enough.
I used Belcoot/Sagiri/Raven (Charge 1/1, Ambush 2/2, SPD +3) and Roy/Cathari/Ernst (Charge 1/1, Recover 2/2, SPD +3) to pursue the Archer units. I found that there were collision issues with the Archers, where an expected battle didn't trigger when I was on top of them. Ambush from Belcoot remedied this slightly. When Belcoot and Roy were interfering with the archers, they immediately started exhausting their barrages on me. I had Roy's unit cast Recovery when needed, then continued pursuing as the archers slipped past me.
This created a sort of pincer attack where the archers were pinned between barrages and thunders from Jeane and Isato, and driven back into my infantry where I managed to finish them off just before the enemy Infantry units took too much damage, which would have prematurely ended the battle before I could finish the last Archer off.
Lucky. I imagine if it weren't for the collision issues, I could have kept the enemy Archers in front of me and finished them off quicker, but that was unfortunate.