If "okey dokey", "okey-dokey", or "okey-doke" just mean okay, then I wonder where the "doke(y)" comes from and what it originally means?
Can I use it in this way?
A: Do you agree with her idea, or not?
B: Okey dokey
This is called "reduplication" and rhyming reduplication is quite common casual English "super-duper, easy-peasy" The word "dokey" is just a modified version of "okay" with an arbitary "d" attached to it.
The existence of "hokey-pokey" probably influenced the reduplication of okay to okey-dokey
In terms of meaning it is just a very casual and silly form of "okay". You can't reply to "Do you agree, or not?" with "Okay". You need "Yes" or "No". (I suppose you could say "Okay, I agree".) "Okey-dokey" is silly talk, unless you are being deliberately silly, I'd suggest not using it at all.
"Okay" and "Okey-dokey" can be used to indicate agreement to an instruction, not to a question:
Wash the dishes!
Okey-dokey, I'll get right on that.
Okey dokey is kinda Old School...
Why not try, "Aye Aye Captain!" instead?
It has the same thought that you agreed, while showing the other side of your Humor.
or you can also used; "Sounds like a plan." to confidently express that you're down whatever they would like to do. It's way more professional and sounds cooler than; (Yes, Master! / I obey / as you wish / and R.O.G.E.R. that!-which stands for Received Order Given, Expect Results -I've just once wonder who the hell is ROGER? haha so I find out it was an Acronym)
Simply saying "Sounds like a plan." in response to orders, objectives or commands - will give more impact that you somehow appreciate their idea to deal with specific things. (While playing safe and not to be blame with the accountability when it fails, because you simply obey to and do what they want. haha!)