You can see the PoC enemy portrait (but not name) at the screen where it asks you to click start to begin the battle (the screen that pops up after the battle music starts up)
The commander you described is Maginot. And it is a very bad stroke of luck when you get her instead of almost anything else in that stage bracket (though Corrupt Thor with her stun attack can be a pain too). Normally her screenwide AoE shouldn't hit your lieutenant/commander, though. Maybe it's possible for her to hit your commander with it if you have your own tanks next to your commander so your commander receives the splashed damage, I suppose. In that case, because her AoE screen attack comes at set time periods (I forget the exact number of seconds in between uses but it's always the same), the solution for your commander to avoid it is to just make sure you don't deploy any tanks around the time she's about to use it.
There's no way to protect your tanks from it directly though (of course, you can use defense-increasing skills when it's coming but that goes for anything an enemy throws at you). Which is real BS sometimes, especially how you basically can kiss any artillery tanks of yours good bye after a few moments no matter what. She's still beatable if you're outlevelled for that particular PoC stage you're doing, but otherwise all you can really do is just lose and try again and hope you get a different enemy boss.
I wish they'd rebalance PoC to take into account the enemy commander you get because some like Maginot are just ridiculous and they really should add something like making the deployed enemy tanks inferior for whenever she's the enemy commander to balance that out. Of course, when you get to stage 21, you can start running into Gustav instead and she's even worse. Waaaaaay worse. Pretty much an auto-lose-and-retry-hoping-for-something-else enemy commander even for the strongest players in Nutaku version right now.