Answer: SLOWBRO
Explanation: The episode referred to is Island of the Giant Pokémon. Slowbro was "Who's that Pokémon?" in that episode.
Answer: CUBONE
Explanation: Well, the ghost Marowak was Cubone's mother, wasn't she? Can't get much more related than parent and child.
Answer: ALTARIA
Explanation: "Alt" is a type of voice (specifically, a deep female voice), and an "aria" is a type of musical piece.
Answer: REGICE
Explanation: I and some others have referred to Regice as the "ballerina ice cube".
Answer: ZAPDOS
Explanation: Zapdos is a very spiky Pokémon and it's powerful, but it doesn't actually use any 'spiky' attacks.
Answer: FLAMETHROWER
Explanation: Just looking at the word "Flamethrower", it sounds like something that throws flames.
Answer: DRAGONAIR
Explanation: Dragonair was in the episode "The Legend of Dratini", which was banned for showing guns.
Answer: CYNDAQUIL
Explanation: Cyndaquil has extremely little in common with a mouse, so it's a wonder it ever got that classification. It's obviously based on an echidna.
Answer: LEECH LIFE
Explanation: Zubat is one of the most avid users of Leech Life, but sadly, Leech Life has 20 power and is a Bug attack, so Zubat doesn't do a lot of damage with it.
Answer: SCIZOR
Explanation: Scyther, according to the animé episode "Showdown in Dark City", hates the color red, so it's interesting that its evolution is red all over.
Answer: UNOWN
Explanation: This is both an individual pun (spelling and the fact that Unown form an alphabet) and a reference to the title of the third Pokémon movie (Spell of the Unown).
Answer: MOLTRES
Explanation: An inside reference - at the Cave of Dragonflies forums, people can post Pokémon sprites by typing the Pokémon's name in between two colons, and while most of the sprites that can be shown in this way are straight from the games, Moltres is one of the Pokémon that has a customized sprite.
Answer: WHITESMOKE
Explanation: An inside reference - the forum member Xikaze adores Torkoal, and White Smoke is Torkoal's ability which no other Pokémon has.
Answer: MAGNETPULL
Explanation: Magneton's ability, Magnet Pull, is one of the reasons it's most likely the best Skarmory counter around in competitive battling. Magnet Pull prevents Steel types from switching out, leaving poor Skarmory helpless to be fried by a Thunderbolt.
Answer: SCYTHER
Explanation: An inside reference - I like to say "FWEE, SCYTHER!" wherever Scyther is mentioned.
Answer: GRUMPIG
Explanation: Spoink's Japanese name is Banebuu.
Answer: YANMA
Explanation: A common Pokémon forum game is "The Last Letter Game" where you have to post a Pokémon in whose name the first letter is the same as the last of that of the Pokémon posted by the above poster. Many Pokémon's names end in a y, but Yanma is the only Pokémon whose name starts with one, which is very convenient for such games.
Answer: TENTACOOL
Explanation: In least favorite Pokémon threads, Tentacool always pops up, the explanation being that it's so annoying that you can't surf anywhere without being attacked by a dozen of them...
Answer: VOLTORB
Explanation: Voltorb is infamous for its resemblance to a Pokéball, and it explodes, which makes it rather dangerous for people who attempt to pick it up.
Answer: SHEERCOLD
Explanation: -273.15°C is absolute zero, and in the Japanese version, Sheer Cold is called Absolute Zero.
Answer: CHARIZARD
Explanation: The Pokédex says Charizard's fire is hot enough to melt boulders.
Answer: ANDUATH
Explanation: Anduath is a fake Pokémon created by forum members for the short-lived Dragonfly Times.
Answer: PIKACHU
Explanation: Pikachu is both extremely popular and extremely hated by those who dislike it for being overpopular.
Answer: WILLOWISP
Explanation: This one is rather obvious - Will-O-Wisp is a Fire attack, but it is most famously used by Ghost types.
Answer: ONIX
Explanation: The two Gym leaders are of course Brock and Jasmine. While Jasmine trains Steel Pokémon and has a Steelix, an in-game character mentions that she used to train Rock Pokémon like Onix, which shows that obviously, she simply ended up evolving her Onix and switching to a Steel-type team.
Answer: FOCUSENERGY
Explanation: Well, focusing one's energy sounds Psychic-like, similar to Meditate. The trap here is that you could think it means a Pokémon, and obviously won't find an answer since no Pokémon has 11 characters in its name.
Answer: CHARM
Explanation: The move Charm is learned by a lot of baby Pokémon.
Answer: FLYGON
Explanation: Flygon is a dragonfly, and it's the Cave of Dragonflies, so it's fairly obvious.