I have a great solution thats in my head for a while that will help.
If the choson and kallah teacher would be a married couple. she teaches the girls and he teaches the boys, so first of all the choson and kallah would be on same page, and should any issues come up in the future it would be much more simple to solve cause the choson teacher will be able to discuss it with at the kallah teacher face to face in a timely manor and much more openly.
Im thinking of doing this myself and my wife for a while. She is perfect for this, a great teacher and communicator, I believe that any choson and kallah that will be coached by me and my wife will a great and long lasting loving relationship ,and avoid many issues that come up down the road
I want to add one more point, i think its essential that choson kallah go one year after their marriage back to their choson and kallah teacher .