They are compatible as long as they fit inside the tube, agreed.... However, you then have the issues of the friction of the expan inside the metal tube and the added weight of the background. They were designed to work inside the cardboard cores of paper rolls where there is more friction and less load. The Manfrotto expans have for some time now been labelled 'B/P' for Background paper, and that is what they are recommended for.
In your case with Autopoles you then have the issue of the weight of the background at height without a firm fixing. Remember that the maximum load will be when you are actually raising the backgrounds, and the Autopoles relies on expansion to stay in place.
I am currently being consulted by a solicitor acting for a client who was apparently injured when a set up similar to yours collapsed during a shoot: Manfrotto publish weight limits for their equipment- exceed them at your peril. Most other manufacturers do not publish such data, and will rely on the common sense of the end user.