Thanks for pointing that out! I forgot to add the link. Just added it, and here it is: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-0CgGAK9yLLM.html
Expired film is actually pretty reliable to capture an image. If it's recently expired it should look almost normal, if it's 10 to 20 to 30 years expired, you will get color shift and added grain. I've even seen people develop 60 year old film and still get an image, so you should be okay :)
Yeah, it's about as simple as you can get for a film camera for kids! Just make sure to have them only take pictures outside when it's sunny. Otherwise the images will be too dark.