I can't speak with any authority about Colson's theology but just want to toss out this idea in regard to his ecumenicalism...He's often accused of being ecumenical to a fault but I don't see him having a theological role. More than anything he's attempting to reform culture. When fighting the culture war is it wrong to cooperate with other denominations that share the same values for the same reasons? Can't he do this on the one hand while personally denouncing their theology?
As for his wife being RCC, I assume he was married prior to his salvation. He shouldn't divorce her should he?