What's the best way of handling ecumenical relations?

[CutlerB]

With the 500th anniversary of the Protestant revolt coming up in 2017, the differences between the Catholic Church and Lutheranism will probably be of quite big importance in the future. The Evangelical Church in Germany (EKD) is celebrating this historic movement in the years running up to 2017 with different themes for each year.

I expect that the anniversary will cause discussion about ecumenism, depending upon how each of the churches handle it. While thinking about it, I thought it interesting to ask you what you think about all of this:

1. How would you like to see ecumenical relations and a possible reunification approached?
2. Do you know of any defined Catholic attitude to this, that is, e.g. “non-negotiables”?
3. If you could give the year a motto, what would it be?

I’d be really interested to know how all of you see the chances, and all of the above.