With many figures from M&M powers are activated by using a free action. Since nothing listed in the rules documents have allowed use of a free action during an opponents turn, am I to assume that the only defensive power that can be used by Super Adaptiod is Barrier? Please explain any other nuances with free actions and special powers if you have the time. Thanks a lot.

Eh?
There is no requirement that the power copied needs to be action-activated - once copied, Super-Adaptoid can use said power as much or as little as he wants per the standard requirements of the power.
He can copy all the Invulnerability and Impervious he wants.

Or just read Quebbster's answer.


That works, too

Thanks a lot.