Triggering Shutters

First, most shots like this either start with the effect, then the camera continues on, or finish with the effect, or have the effect in between two shots. You have to be extremely careful to line up your video camera with your still cameras, so that the effect looks like part of the shot, not a bunch of scanned film frames.

Second, there's always the obvious film vs. video difference. I've got a GL-1 and some rudimentary lighting training. The most pristine, beautiful shots I can get on video still suffer in comparison with film (esp. 35mm, which is the size inside the consumer disposable cameras). You have to make sure that you degrade the stills once they're in the computer, to match the footage.

Third, your lens setup. Disposable cameras have a prime lens (that isn't that prime), usually in the 28mm range. Most video cameras, at full wide, give you the SLR equivalent of something like 40mm. When shooting this effect for movies, they use the same focal length lenses on the still SLR's as they do on the motion cameras. Your angle-of-view is going to change, as well as the proportions and relationships of foreground to background when you cut between still photos and video.

Fourth--aspect ratio. Consumer 35mm, which is developed by automated machines often, seemingly arbitrarily, cuts off differing portions of each frame. When you scan the photos in, you have to both make sure you have the subject in the same position in each frame (so that as the camera "turns" the subject doesn't jump around in the frame), and you also have to crop consistently (video is 4:3, film is 1.85. . .in theory), to avoid the same type of problem.

Last, in specific response to your question about disposable cameras--certainly, look up things and try to rig some stuff. I don't have the pro experience in shooting this effect, but I have worked for quite a long time with SLR's. To set off a shutter at an exact moment, the cameras are all tripped at the same time, via A) a cable release, or B) a flash-sync. The problem with disposable cameras is that they do not have cable release capability, or B) a hot-shoe that accepts a flash-sync unit.

Lame answer, but disposable won't work very well, if at all. The cameras are pitched at boy scouts going on campouts, families without cameras on vacation, etc. They're not very durable, and I don't even know if you can mount them on tripods (kind of important for this kind of effect).

I'd recommend pulling upon the generosity of your local camera dealer. . .in giving you some tips, and perhaps a discount on some camera rentals.

Personally, I favor the actors-hold-very-still, and move the camera on a dolly very quickly, play with the footage in post (slow it down, speed it up), and then edit it together. Fast-cut MTV-style editing can exist for more than music videos--it makes it easy to make a discontinous action sequence flow ultra-smooth.