It really depends.
If you're a melee, I think the easiest cell would be cell 1, with the 2 Red Wolves and the Industry Giant. They're slow, easy to hit with melee weapons, and relatively easy to dodge.
You probably won't want to fight cell 3 as a melee character (2 Two-eyed Monstrosities & Guttermouth Effigy), because the Effigy moves like Sonic, and would be hard to hit with Melee.
The hardest cell, for any class, would probably be cell 2. Two Crickets and a Nightmare Lantern? Yikes. The AOE attacks and the almost-guaranteed-to-hit laser from the Crickets would overwhelm any player, not to mention they sound weird.
Anyways I hoped I helped, and good luck.
The cell with red wolves and giant is just 2 ez 4 me.
What do you think?