Arknights Welfare TG-4 Clear, Challenge Mode

To the Grinning Valley level TG-4, Frozen Circle, Challenge Mode, cleared using only 5 Welfare operators.
I put Gladiia, using her first skill, on the Specialist Tactical point and let her pretty much handle all the enemies coming in her lane. For the upper lane, I placed Puzzle to generate DP, though he doesn't survive his first contact with the Enraged Possessed Leaders, because of this challenge level's reduced defence gimmick. Instead, I use Astgenne and Nine-Colored Deer to whittle the enemies life away before they get to the gate. I add Harold for healing Puzzle when I bring him back as a last defense. At the end, I screwed up a bit and didn't engage Astgenne's skill soon enough, so the last Possessed Leader got to Puzzle and killed him (even Harold's skill couldn't keep him alive). But, Nine-Colored Deer managed to kill the enemy before he could get through the gate. It was a close one, and I should have planned my skill use better to avoid that. Oh, well. A clear is a clear, right?
Welfare operators are as defined at:
arknights.wiki...
wiki/Operator/Welfare.
Comments and advice are always appreciated.