Good vent, Cliff.
Between Cindy & I, we have one "sibling"...Cindy's brother, he a religious con man. So, to answer your question..no, she and he do NOT get along.
As to eloping? Cindy & I were married on June 25, 1975...the Reno courthouse with strangers as witnesses. Both of us dressed in Jeans & T shirts.
We're still here.... How many $$$$ weddings have since resulted in divorce? Probably about the same %age as Reno courthouse weddings, I'd surmise.
The wedding isn't the thing. How you work together is.
(edit) When you marry someone, you, in a way, also marry their family. I hope that both of you are strong enough to overcome this obstacle. Your bride should become the most important person in the world to you. You will need to tolerate a lot of family ***** for years. But keep in mind...parents and older siblings usually die before you do...the family problems do diminish, given enough time. Sometimes, that time can be decades.
But what do I know? I'm an old fart...