I remember back in the WoTC days that they were "frowned upon" but I don't know if they were ever banned. I know for a fact that many players had found resourceful friends that could alter them so that they would no longer flip randomly. I had one but after their cover was blown I retired mine...
I'm pretty sure it'll be able to be used first turn. From the flavor/storyline continuity standpoint Jirachi should be able to screw with game rules.
Now I'll put on my sceptical TCG'er hat and venture to say that it is possible that this issue could take the Omanyte route and just confuse...
Actually Steven's Advice says:
"Draw a number of cards up to the number of your opponent's pokemon in play."
"If you have more than 7 card (including this one) in your hand, you can't play this card"
Why use Nurse if you don't have any way to retrieve energy from the discard? Sure you are...
Is damage from attacks applied between turns? Are attack effects applied between turns? The answer is "No" to both questions. So the answer is the same for "Make A Wish" its an attack that has an effect.
The only Supers I have are both of the light ones from BS (Hanusa and Urth), but I do have full play sets of them both. Most of the rares and lower from the other civilizations, I also have.