MTG Salvation

1. I control Mirror Entity and Scion of the Ur-Dragon. I active Mirror Entity for 3. I activate Scion, making it a copy of The Ur-Dragon. What's Scion's power/toughness?

2. I control Mirror Entity, Shapesharer, and Headless Horseman. I activate Mirror Entity for 10. I activate Shapesharer, targeting Gray Ogre and an opponent's Dwarven Pony. What's Headless Horseman's power/toughness?

Edit: Corrected Gray Ogre/Headless Horseman error.

1. The Scion is 3/3. Mirror Entity's ability makes it 3/3, which layers over top of the copy effect (which is the first layer).

2. I don't know where the Gray Ogre came from, but if it was a creature permanent when the Entity's ability resolved, it is 10/10. The same reason.