Alright, I consulted CAP's resident GPer regarding grammar and have thus come up with the slate. Please note the having flawless grammar is a requirement for being slated, as stated in the thread's OP. I'll make the poll later when I get home; I'm in a bit of a time crunch right now.
The slate:
Amitghosh
Final Submission
Kerfluffle, the Fluffy Pokémon
X/OR: Weary Pokémon often fall asleep on wild Kerfluffle, mistaking them for pillows. Most of them never wake up again.
Y/AS: Tame Kerfluffle are popular in Pokémon Contests, as they make an excellent pair with sleeping Munchlax. They like taunting their opponents and fleeing right after.
Deck Knight
Final Submission:
Kerfluffle, the Right Stuff Pokemon
X/OR: Kerfluffle can knock out a grown man in one punch - but it always carries the opponent to their bed to recover afterward.
Y/AS: Kerfluffle's stuffing is made of tightly woven muscle fibers that allow it to be as rigid or soft as the moment requires.
Falchion
Final Submission
Kerfluffle, the Pillow Fight Pokémon.
X/OR: It is thought to have arisen from a pillow bathed in mysterious rays. Its playful nature and pleasing scent incite others to frolic with it.
Y/AS: Able to dodge attacks with surprising speed, it is friendly but loves to roughhouse. Occasionally, its strange gestures may be mistaken for aggression.
iwantalolly
Final Submission
Kerfluffle, the Punching Pokémon
X/OR: Kerfluffle enjoys to yell and thrash about before seeking refuge to protect itself.
Y/AS: Kerfluffle adores playing with people and Pokémon. However, it usually ends up injuring someone because it likes to be rough and use its fists.
LucarioOfLegends
Final Submission
Kerfluffle, the Play Pillow Pokemon
X/OR: Kerfluffle's body is extremely light and fluffy. This allows it to avoid attacks and strike at blinding speed.
Y/AS: Kerfluffle enjoys toying with its opponents through verbal taunts. An especially mischievous one will even mess with its own Trainer.
Pika Xreme
Final Submission
Kerfluffle, the Pillow Fighter Pokémon.
X/OR: It is a born fighter. Even untrained, it can withstand over 100 tons of force. It often teases its opponents.
Y/AS: Despite its soft appearance, it is a very strong Pokemon. It can knock a Delibird out of the sky with a mere Fairy Wind.
Yoshiblaze
Final Submission
Kerfluffle, the Punchy Pillow Pokemon
X/OR: Using its pillow-like hands, Kerfluffle protects its trainer at all cost from any danger. Kerfluffle will often try to intimidate threats by calling them names.
Y/AS: Kerfluffle is a playful Pokemon that enjoys being around humans, but it will get annoyed if a human or Pokemon tries to sleep on it.
Below are the final submissions that did not make the mistake and the reason why they were DQed:
KirisameAlice: although his/her entries are flawless, he/she misspelled Kerfluffle in the line "Kurfluffle, the Body Pillow Pokémon".
Rasdanation: he/she use "it's" instead of "its" in their X/OR entry, and the second sentence of their Y/AS one is messy in terms of prose.
GreenGogoatttt: his X/OR entry desperately needs a comma, and he fails to capitalize Pokemon in his Y/AS entry.
snake_rattler: he should have used victims' instead of victim's for his Y/AS entry, as "Many of its..." implies that Kerfluffle will probably live its life making more than one Pokemon its victim.
Willow616: he/she fails to end his/her entries with periods and displays general grammar mistakes.
Viridi: he/she uses a comma splice in his/her Y/AS entry.
KeeganSkymin444: he changes tenses from present to past and back to present in his Y/AS entry.
ThePsychoBear: his Y/AS entry contains a sentence fragment and comma splice.