regardless the players guide is still in effect even after the new rules come into play. The new rulebook will override most of what the playersguide says about certain powers, but that does not mean the players guide is not usable for all other effects and corrections.

so, what's the final verdict regarding Multi-attack and Colossals with their own rule sheet? I thought that if there's a rule sheet for the Colossal, then that is the one that's followed.

In other words, Dark Phoenix can continue to push without taking damage.

Was Dark Phoenix ever able to RS twice and now after the the new rules are in effect, she won't be able to do so anymore?

No Cause under the new rules they would have Colossal Stamina and take Unavoidable Damage. As well they would have to follow the new rules for Multi-Attack as written in the PAC.

Edit: The only one that has a Different Power is Galactus (Original) with Cosmic Multi-Attack

Then that is in contradiction to this statement in a rules article published on April 16?

Which is correct?

Edit:
I thought maybe Colossal Stamina is a general rule and the rule sheet is the special rule so the special rule would trump the general rule.

Yes and for a lot of colossal figures with special rules the prevention of pushing damage is due to having a team ability which would not prevent Colossal Stamina Unavoidable Damage, such as Dark Phoenix. There are only a few that have "this character does not take pushing damage" written separately from a team ability: both Galactus, Fin Fang Foom, and Starro.

I dont think that was what Norm was trying to convey. Seems pretty straight forward to me that if said old colossal didn't take pushing damage before then they should ignore this UA damage for the new colossals.

Actually he said it was up to judges discretion until an errata by GD has been determined.

Duo attack says specifically that you make the attacks, Multi Attack says you get 2 actions as free actions.

From the 2011 Rule book
A basic Attack is an action unless grated by another power or combat ability.

Right or wrong, every ruling is up to the judges discretion.