You want a Nikon R10. The footage is incredibly sharp and stable (for Super 8), It'll do what you want. It's more user friendly than the Beaulieu and the Leicina.
If you have to have everything on the list (e.g. must have f1.4), you're stuck with three cameras. The Nikon R10, the Leicina Special (which won't do 24 FPS) or the Beaulieu 4008 (a bunch of other Beaulieus will do what you want, but the 4008ZM2 or ZM4 are your best bets). The Leicina will need a lens adapter, as the Optivaron is f1.8 fully open.
The Leicina (Leica M mount) and Beaulieu (C Mount) can both use interchangable lenses. With adapters, both are capable of taking some seriously sharp glass (PL mount adapters exist for both).
If you want a good introduction to filmmaking basics, I recommend The Filmmaker's Handbook:
Servicing a camera will cost a fair amount as well. I haven't priced it out in a while, but figure at least $300 for an unknown camera. Nikon and Leica stopped making cameras in the late 70s. The last Canon was built in the early 80s ('83 maybe?). The last Beaulieu was built in the early 90s. The only camera built since then is the Logmar (with a $$$ pricetag).
You could always buy a camera for cheap off ebay, cross you fingers and shoot a test film. I've gotten very nice cameras by doing this.
Film types... you 've got two (maybe 3 if you're willing to scour the globe.) Black and white reversal, or color negative. Color reversal used to exist and some people in Europe still have it. Reversal means it can be projected as developed. Negative means it needs to be converted before it can be used; either a workprint or telecine. Some people love one or the other. Personally, I prefer the Kodak color negative stocks for shooting footage and Tri-X for test films.
Developing... you're best off handing that off to a lab. It's tricky work (especially for color negative).
Also, keep in mind that film will run around $26 per cartridge. That's about 2min 40 seconds at 24FPS. Figure another $35ish for developing and telecine, per cartridge.
You can get film from Kodak:
I always like Cinelab for processing and telecine.