Your jacket is breathtaking and a huge congratulations on you completing such a beautiful piece of art. Have a wonderful time wearing your beautiful creation.
While I did not make something so elaborate just a velvet cape for my grand-daughter I found that stapling the edges, right on the very edge worked great. I serged most of this so a walking foot could not be used but as silly as it sounds my staples saved my day! I was fighting the movement of the material till I got mad and the stapler came out. It has to be at the very edge of the fabric especially if you are using a serger but it really did work well.
Good luck on any of your new projects.