two Powerhouses? bah you said the world energy, as stated Powerhouse can absorb energy plus his own bio stats he can be ok in radiation, and to what Khan said, neither would HIS team....
also Duplicate Boy was shown to take ANY power he wanted if I had scans I would get them, but I will try in the time being get the scans when he fought Collossal Boy using Mon Els powers and Element Lads powers. Also Powerhouse would still have a gravity field taking place, so even if he tried this move you characters would still be slowed down considerably.
DB has anyones powers period, if he wanted he could take RM's powers and use them agains the team, but that would just negate him, allowing the rest of the teams to fight.
Another factor would be the fact that Duplicate Boy has already taken the powers of almost all legion memebers and used them effectivly, he can learn how to use a power easier than most, but not instantly. Gravity Fields give me time to move my Wendigos around your characters, making Speedfreak slower and Radiation man would be harming everyone in the feild if my Wendigos and your Animal Men are fighting with Speed Freak in the middle too.
Crytal can still create an earthquake, or tornado mixed with the lightposts and water, create water to make a typhoon, or create a duststorm, making visibility worse in your direction