Thanks for showing the photos. I showed my dad the link, hes a bit of a amatuer camerperson. Hes first opionion was similar to mine, it appears to be light leaking into the camera, as the images always appear on the right hand side. Because you used different cameras, Dad suggest it may be how your loading the film, allowing light to leak into the film. He says you should always keep your back to light when loading a film.
However, the one with the ring like image has us both stumped.
You may like to do a process of elimination, get someone else to load the camera with the film for you, take the film to different processing places, and so on.