Well, about 10 stamina potions and many attempts later, I finally managed to cobble together a team that could conquer the current GHB. This was my very first Lunatic GHB victory. A lot of y'all mentioned how easy this one was, but none of my higher level units were equipped to deal with all the stuff this battle threw at me.
Anyway, my winning team was 5* Ephraim, 5* Spring Lucina, 4* Cherche, and 4* Eirika. I was lucky to have the Cherche, it was an early unit that I leveled up before I knew anything about IVs and she's -ATK (with no boons at all, according to the IV calculator), so I never would've wasted time on her with the knowledge I have now.
The whole story of how I figured everything out could be a Tolstoy novel, so I'll just cut to the chase and say that the ultimate solution involved:
- (1) feeding one of my dozen trashy Donnels to Ephraim for Brave Lance and Drag Back (I got this idea from the 3* strategy guy on YouTube)
- (2) using Cherche's Fortify Def to further tankify Ephraim, and
- (3) a liberal use of Cherche and Eirika's Pivot abilities (and Eirika's Drag Back) to take down the troubador and the knight while Ephraim and Spring Lucina ganged up on Navarre and the final ninja.