Since you seem to have exact dates and places of birth, the next step for your Swiss research is to order the microfilmed church records at your local LDS Family History Center. This is by far the simplest and least expensive alternative.
The Family History Library catalogue (on FamilySearch.org) has the microfilms of the church records of the parish of Castiel, which includes Castiel, Lüen, and Calfriesen, covering the years 1685-1875. Use the catalogue to get the microfilm numbers that you need to have sent to the local Family History Center. Even farther back, it's possible that these towns would have been attached to some other parish, something you can discover by learning more about the local history and geography. I'm not sure all parishes in the canton of Graubünden were microfilmed, but as luck would have it, the camera crew was able to get to the parish you need.