You have many suggestions to help you.
I believe that the exercises will help slow the progression of bone loss; just, start out slow and easy in the beginner format with less ROM. Keep a close eye on the clients and make sure to keep open communication with them for any signs of difficulty and poor form. Do not let them lift both arms or both legs simultaneously, either. Have you tried using thick, soft or multiple mats on the floor?
Not to mention, how many of us have disorders that we are not aware of?
Good luck and enjoy keeping the seniors healthy.