According to my research, you can have analogue films developed at various laboratories and companies in Switzerland. This possibility still exists. Unfortunately, I don't have a recommendation as such, as I only take digital photos myself and can't share any experience here.
A film is not included.
Yes, films that are developed in the C-41 process are very 'good-natured'. (Almost) any colour film will work.
I would also try out black and white films; in good lighting conditions a rather fine-grained film (e.g. Kodak T-Max 100, Ilford FP4 or Ilford PanF), for more difficult lighting conditions an Ilford HP5 or a Kodak T-Max 400 would be suitable.
Another good alternative is Ilford XP2, a black and white film developed in the C-41 process.
What do you mean by double images? The camera simply puts twice as many photos on the film due to the reduced frame. The photos are slightly lower in resolution, but otherwise quite "normal". Only the orientation is different. In other words: camera horizontal = portrait / camera vertical = landscape. It's a great thing! :-)
The image quality is even worse because only half of a 24x36mm image is exposed. So 18x24mm. So-called half format. In digital times known as APS-C, by the way. You can probably have the pictures printed right away. Will that work? I don't think so.