According to the common opinion of theologians, and apparently, the Vatican, the teaching on religious liberty, in the limited and restricted sense in which the Council Fathers and magisterium after Vatican II teaches it, is most likely a level 3 or level 4 teaching. It is at the least part of the "authentic" magisterium, issued in a solemn ecumenical council. Or it is a development (NOT a contradiction: Any trads OR modernists who interpret it as a contradiction of the previous, continuous ordinary magisterial teaching are both in error, and is a teaching of the ordinary magisterium. In either case (level 3 or 4), it is owed the "religious respect of mind and will" referenced in Lumen Gentium due to all teachings of the living or ordinary magisterium. Levels 1 and 2 are believed to be infallible teachings. Just because DH is not necessarily infallible, does not mean Catholics may freely disregard it or call the ideas of its texts into question. "Religious assent (respect) of mind and will" means exactly what it says.
Let's keep a focus on the Cardinal's brand of ecumenism. I'd be willing to be sidetracked eventually, but just for now...