can ANY power(EW, BCF, EE, PB etc.) be used while using the Duo ability?

The only ones I believe will work are Super Strength and Steal Energy.

Damage reducers also work (for example, if you close-combat clobber with the Fuel Tank), as does Willpower.

Edit: also the part of Leap/Climb that allows close combat against different elevations.

Actually it won't.

DUO ATTACK Give this character a power action to make a duo
attack. It makes two separate attacks against opposing characters as free actions (making two separate attack rolls). These attacks can
be close combat attacks or ranged combat attacks (ranged combat
attacks can have only a single target). Resolve the first attack before
making the second; this character’s damage value is modified by –1
for the second attack, to a minimum damage value of 1. If this
character is defeated as a result of the first attack in a duo attack,
the second attack is not made.

LEAP/CLIMB When you give this character a move action, it automatically breaks away and ignores the effects of characters, hindering terrain, elevated terrain, and outdoor blocking terrain on movement (but it can’t end its movement on blocking terrain). When you give this character a close combat action, it can target a character regardless of the target’s elevation.

You never assign a CC action to activate that part of LC.

Tarnish

Curses! Wrong again! Somebody needs to donate a Cap&Bucky and Power Man & Iron Fist so I will learn these pesky nuances!

Does anyone else think that duo attack should just be changed to multi-attack? it would basically accomplish the same thing without a lot of the confusion... if duos could use their powers (a la multi-attack) they would be great. As it is, they're confusing, difficult to play, and for the most part not worth their points.

Under much discussion here.

http://www.hcrealms.com/forum/showthread.php?t=264737

But to answer your question, no, I don't think it needs to be changed.

EDIT: IIRC, there was never a FAQ entry for the duo ability in the player's guide before WK shut down, so how much confusion could it cause, once you establish it's a power action?

The nature of the duo-attack vs. the multi-attack is such that the m-a is far more powerful than the d-a. To just switch them up would create a massive shift in cost-effectiveness, unbalancing the figures.
People said the same thing about the old giant rules which were actually far more intuitive (and better) than the new ones.

If duos have a problem, it is the same one the original giants had...poor dials.

You could use Enhancement.

Any power that does not require a tokenable action will work with Duo Attack; e.g. Super Strength, Outwit, Perplex, Super-Senses, all damage reducing powers, etc.

The easiest way to remember what powers work with Duo Attack is to ask, "Does this power require a token to use?" If the answer is yes, it doesn't work with Duo Attack.

Duo Attack is a Power Action, so it follows all the same rules as the other powers as far as power compatibility.

A resounding no! Duo Attack and Multi-Attack should remain separate.

Duo Attack is perfect the way it is. It gives you plenty of tactical options. Do you go for two attacks, dishing out more potential damage? Or do you use a power instead to get a certain result. Great tactical options are what make HeroClix great. Don't dumb it down.

Or poor battlefield tactics perpetrated by the player. I've never had a problem using Duo Figs. They rock.

Harpua is so correct that MA is waaaay more powerful that DA, and if all of a sudden I could do Multi-Attack with Thor and Loki and only for 362 points, I would never use another fig again. Especially since I just swept a tourney very easily with Thor and Loki, and that was only with the Duo Attack.

Yes and no.

What I mean is that with the way you phrased your response, a person could get them impression that you mean Outwit or Perplex (for example) could be used in the middle of a Duo Attack; that would be incorrect.

Sure, a Duo with Outwit can counter a power with Outwit on a character, then use the Duo Attack, and the power will still be countered, but you can't use Outwit during the Duo Attack just like you can't move with Charge, Outwit, then attack with Charge. You can't use powers like that in the middle of another action.

Totally, an action must be resolved before another can be made, as in Outwit and Perplex. Thank you the clarification so someone doesn't misinterpret my post.

LOL!, this reminds me of the firestorm of a thread I created awhile back about game ethics and actions. That was a great debate!