1)
Actually it's one reference to attacks and three to powers.
2)
Nothing in the part saying attacks provoke is specifically saying other powers do not. It is not exclusionary. Just like saying 'I can use this Encounter power once per encounter' is not saying 'But I can't use any other encounter powers once per encounter, even tho nothing says that specificly.'
3)
You have three instances of powers triggering OA, and zero instances of text saying they don't. Nothing is contradicting powers (in general) triggering OA, there is no rule saying utility powers are exempt.