Show & Tell + Auras

[FTW]

If opponent casts Show and Tell and puts into play a creature and you reveal an aura, can your Aura enchant their revealed creature?

If that Aura removes abilities like Witness Protection and opponent's creature has a triggered ability (e.g. Atraxa, Grand Unifier), does your aura stop their trigger?

It's just a legitimate business person, nothing to see.

[Zoid]

Usually, if things enter at the same time as an aura, the aura can't target it.

That's why they word it like this:

[FTW]

Yeah that's the standard templating for Warp World and newer cards. But Show & Tell is from Urza's Saga.

Gatherer says that any choices, such as targeting, are made after the chosen cards are revealed and happen in turn order (NAP chooses last). Does that let NAP enchant the AP's card?

If the cards being put onto the battlefield also require choices, those choices are made after all players choose their card. The active player makes choices for their card (if any), then the other players (if any) in turn order.

[FourDogsinaHorseSuit]

You can't, the card you put into play can't enchant something being put into play at the same time.
here's the gatherer entry on Copy Enchantment:

If Copy Enchantment copies an Aura this way, you choose what the Aura will enchant just before it enters the battlefield. You can't choose any permanents entering the battlefield at the same time as that Aura. This doesn't target the player or permanent it will enchant, so an opponent's permanent with hexproof may be chosen this way. The chosen recipient must be able to legally be enchanted by the Aura, so a player or permanent with protection from one of the Aura's qualities can't be chosen this way. If there's nothing legal for the Aura to enchant, Copy Enchantment stays in its current zone (unless it's a spell, in which case it's put into its owner's graveyard).

[FTW]

Thanks for the clear ruling!