Okay, I have a multi-part question about a casual game I played last night with a friend. (We are both only casual players, and we play Unlimited.)
The three cards involved are:
Kingdra Lv. 52 (Diamond and Pearl: Legends Awakened, http://bulbapedia.bulbagarden.net/wi...ds_Awakened_7))
Ditto Lv. 20 (Fossil, http://bulbapedia.bulbagarden.net/wiki/Ditto_(Fossil_3))
Clefable Lv. 34 (Jungle, http://bulbapedia.bulbagarden.net/wi...ble_(Jungle_1))
My active Pokémon is Kingdra when he brings Ditto up from his bench, so Ditto becomes Kingdra. Ditto Knocks Out my Kingdra when Ditto has 10 damage counters on it. When I then bring up Clefable as my next Active Pokémon, does Ditto become Clefable and automatically faint because it has 10 damage counters on it and only 70 HP? That's what I thought, but he said its Pokémon Power should be treated as a Poké-Power rather than as a Poké-Body, and so he had the option of when to use it. He said he wasn't going to use it, so it is still Kingdra, and so I let it go.
Later, on my next turn I tried to use Clefable's Metronome to copy Ditto's Dragon Pump, and I thought I could do 60 damage to Ditto and 20 to a Benched Pokémon without discarding anything, but he said no. We had a small debate about it, and I thought I could do this because Metronome says that I don't have to execute costs required to use the attack. My argument was that even though the discarding wasn't required to do the 40, it was required to do the 60 + 20>Bench, so it was required, and I didn't have to discard them. In the end, I let that go as well, though, and we assumed that I had to discard the cards.
On both of these questions, could you please tell me what the correct ruling should be? I don't want to win (or lose) an argument, and anyway the battle's over; I just want to know for the future if similar situations arise (especially on the first question because I'm sure he will use that Ditto again).