"Okey-dokey" has a slight lead over "okie-dokie" in popularity, but the latter spelling is also widely in use. (U.S. dictionaries seem to clearly prefer "okey-dokey.)

Is okey dokey hyphenated?

As a reduplication it is properly spelled with a hyphen, although it is often given without. Like okay, 'okey-doke' is used to indicate that all is well, e.g. 'everything is okay here', but may be used when responding positively to a request. ... See other reduplicated phrases.

Is okidoki a word?

It's a more casual and playful way of saying "Ok". Both boys and girls can use it.