1. Suicune (LV 33) Neo revelation
Pokémon Attacks are always against the Defending Pokémon regardless of what the effects of the attack are (meaning an Eeeeeeek! is considered against the Defending Pokémon which is why it can be prevented).
This means that the Suicune (LV 33) with the Crystal Body Pokémon Power will prevent all effects of attacks done by the opposing Pokémon EXCEPT for damage done to Suicune when Suicune is the Defending Pokémon.
This means that Suicune's Crystal Body WILL prevent Eeeeeeek! This ruling is consistent with previous rulings dealing with Agility and Fetch.
Any other effects that can prevent attack effects against the Defending Pokémon work the same way (such as Agility or Haunter's Transparency).
Also, attacks done by a Pokémon against a Benched Pokémon are considered attack effects and are also prevented by Suicune and Agility like effects. This means that an attack that would do 20 damage to one of the Benched Pokémon WOULD be prevented by an active Suicune or a Defending Pokémon with an Agility status effect on it.
This also means that Suicune's Crystal Body Pokémon Power is not effective when Suicune is on the Bench. Since all attacks and effects of attacks are against the Defending Pokémon, there is no effect targeting Suicune specifically to prevent, even if the attack results in something happening to Suicune.
2. Sneasel (LV 32) Neo Revelation
Sneasel's Swipe attack (Flip a coin, if heads, discard all Trainer cards attached to your opponent's Pokémon) affects ALL of your opponent's Pokémon. This means that a succesful head flip will remove ALL attached Trainer cards on ALL of your opponent's Pokémon.
3. Unown K Neo Revelation
The Keep Pokémon Power is played as written. Whether Unown K is Asleep, Paralyzed, or Confused this Pokémon Power still functions.
4. Healing Field
If you have flipped to use an in-play Healing Field and then play another Healing Field you would be able to flip to use its once-per turn ability. When the previous Stadium card is discarded, it's once per turn status effect is removed as well.
5. Raichu (LV 39) Neo Revelation
Raichu's Lightning Strike attack says "You may discard all lightning energy attached to Raichu. If you do so, this attack does 80 damage." If this attack is copied by another Pokémon (Clefable's Metronome, Smeargel's Sketch, Ditto, etc.) that copying Pokémon can choose to discard all attached lightning energy cards to have the attack do 80 damage as well. This can be done REGARDLESS of whether there are any attached lightning energy or not (you can discard 0 lightning energy to make this choice as long as there aren't any lightning actually attached).