It all depends on what you are shooting. However, a broad hint would be to look at what focal lengths are available for dedicated DSLR Video lenses.
They would not be made unless they were selling.
It's worth mentioning that the ZE's have the same optics as the CP.2's and at a much lower price. Sure you don't get manual iris, built in follow focus gear, uniform size and a few more iris blades, but they're way way cheaper and still solid lenses. Especially for a beginner. You can shoot video with Canon lenses just fine, it may not be as easy as it is with cinema lenses, but it can be/has been done.
As for Corey Kaye and wide shots in filmmaking, I would say 24mm-28mm on full frame is what your average wide shot in a movie is. 16mm on FF is ultra wide and isn't quite as common but some may choose to use it. There aren't really any set rules, whatever you can make work really, but I would personally try not to overuse ultra-wide shots.