Found a website (Luxroots.com) the other day that includes a database of Luxembourg births. I was able to get a temporary membership (which seems to have expired already), and did some searches. I found a Dominique Engelmann, born April 8th, 1859 in Hosingen, Luxembourg. his parents are listed as Urban Engelman, 26, and Maria Catharina Koeth, 28. I am 99% certain these are Urbanus and Maria Engelmann. Further searching confirmed birthdates on Peter, Urbanus, and Catharina Engelmann, as well as Marie Catherine Koch.
I also found a website that lists Pierre Engelmann (Urbanus's father from the database), and takes the Engelmann's back two more generations (one of the branches goes all the way back to the 1690's).
Unfortunately neither of these sites is in english, so I am having to do a little interpreting to understand all of what they can tell me (fortunately dates are the same).
Now if I can just confirm Elizabeth Blanch Ring's family.