Heres my guess, still haven't got the last 2 though

Easy
1. BEAST
2. Ripper EVO
3. Pillow Torque
4. Terrorhurtz
5. Chompalot
6. Meggamouse
Medium
1. Block of Wood
2. Baramot
3. Dragons Claw
4. Pug
5. 4 4 Toon
6. Behemoth
Difficult
1. Maelstrom
2. Thor
3. Wedgie
4. Whirlpool
5. Annihilation
6. Apocalypse
Very Hard
1. Tilly EVO
2. -
3. -