is there a way to play those card in the same attack ?

Play Need for Speed only during your first attack this turn.
Whenever target attacker causes breakthrough this attack, ready that character, and it cannot cause breakthrough this turn.
and
Play Dominated only if no defender became stunned while under an opponent's control this turn.
If target Future Foes character would cause an amount of breakthrough this turn, instead, you may stun a character with DEF less than or equal to that amount.
i guess dominated..../stun def/ play need for speed/ play the trigger effect of dominated ??

and Q2

Whenever Emerald Empress stuns a character an opponent controls, recover that character. This power triggers only once per turn.

Boost 1: When Emerald Empress comes into play, you may search your deck for a card named Emerald Eye, put it into your front row, and shuffle your deck.

if Emerald Eye hes already in play from (round 2) ...when Emerald empress comes into play boost 1 (round 3)....do i need to k.o my other emerald Eye? or i can keep my old and my new emerald Eye in play?

Wow, interesting question.
While you CAN play Need for Speed and Dominated in the same attack, there is no way to get both of them to "do their thing." Dominated is a replacement effect, not a triggered effect.

If Dominated replaces the breakthrough with a stun, your attacker did not cause breakthrough, and therefore does not ready.

If Dominated does not replace the breakthrough, your attacker may ready, but you won't get to stun an opposing character.

You get to keep both. KO due to uniqueness only happens for Recruit and Substitute. If you can find another way to put a character card into play, it does not KO other copies of that named character.

I'm bad at chain stuff, it's possible you can do that, I would imagine you need NFS to resolve first, so the order you have is probably correct, play dominated during the attack, then chain NFS, NFS resolves when Dude causes breakthrough, Dude readies, then dominated resolves to stun in lieu of breakthrough


Your second is easier, if the effect (most common with boost effects) allows you to put a certain character into play, unless the card says "put X into play if you don't control a character named X" then the uniqueness is not checked (see classic 3-drop MSM Mysterio)

Card text can overrule the rules

EDIT-damnit, took too long AND I suck

Like Eric said, the key is to realize that Dominated does not use a triggered effect. But the term "replacement effect" isn't quite right either---in fact, it's not an effect at all, which is why the replacement doesn't use the chain. Here's how the two cards work---

1) You play Need for Speed, and after players pass it resolves, setting up a delayed triggered modifier. When the attacker causes breakthrough, the delayed trigger is triggered, generating an effect, which will go on the chain after attack conclusion has finished.

2) You play Dominated, and after players pass it resolves, setting up a replacement modifier. If the targeted character would cause breakthrough, the replacement modifier steps in and allows you to replace the breakthrough with a stun. If you decide to use the stun, then the breakthrough never happens at all; like the text says, the stun happens instead.

So, like Eric said, the two cards can never both work on the same attack; using Dominated means that breakthrough never occurs, which would prevent Need for Speed from triggering. Multiple triggered effects can trigger off of the same event, since triggered effects just need the event to happen; replacement modifiers actually stop one event from happening, and replace it with another.

And Bruuu, it sounds from your post like you were thinking about playing Need for Speed after the defender had stunned. You can never do that, since not only does the effect need to target an attacker, but Need for Speed specifically says that it must be played during your first attack. On top of that, the plot twist effect needs to have already resolved before breakthrough happens, so (somehow) playing it after the stun would make it impossible to trigger. All of which means---if you want to play Need for Speed, you have to do it during the attack.