Can cataplexy occur without narcolepsy? and is it possible for it to regress to no episodes at all?

Complex: Cataplexy is part of narcolepsy, which also may or may not include daytime sleep attacks, sleep paralysis, vivid nitemares, but there may be only parts of the syndrome, and the full tetrad is not always present. Cataplexy with out the sleep attacks would be unusual but not unheard of, but get an eeg, just to be sure these are not actually seizures instead.

Yes: it is possible for cataplexy to regress by itself. generally cataplexy is diagnostic criteria for narcolepsy, so if you have cataplexy you have narcolepsy but you can have narcolepsy without cataplexy.