On this part of your question: “the terms transparency, slide, and film. Is there a difference?”
I am a user of slides and film images not a conservator but I can share the meanings of the terms. All 3 are used fairly interchangeably but there are differences:
Film is the broadest term in photography. It is anything that is not a print/paper. It is a transparent material usually with emulsion on it depicting an image. Can be a negative or positive image. Can be large or small. ” He was shooting on 5×7 film in his studio camera” “There is unexposed film in her camera”
A transparency is most always an original, positive image like a slide. But I have had commercial photographers shoot studio work on 4 x 5 inch transparencies for high quality photography for reproduction. So a transparencies can be many different sizes and usually without frames.
A slide is usually 35 mm positive film mounted in a frame that can be run easily through a projector – therefore it name. There are larger and smaller format slides, but the most common is 35mm and they should be labeled as such.
So, a slide is made of film but so are negatives. There are many different formats of transparencies. 35 mm slides are the most common consumer format.