I want to propose but dont know his plans? How should I handle this?

So our 2nd year anniversary is Oct 7th. I want to propse to him on our 3rd year anniversary. And I have a plan to do it. But the only issue is that I do know he would like to be the one to propse, which I'm perfectly fine with. And I know he'd be upset if he didnt get to do it, because he likes to be very romantic and make little special plans and its really sweet and cute <3. But how should I go about this? Should I work on proposing anyways so that if by our 3rd year he hasnt already I can ask the question?
Here's my plan if you're interested xD I'm proud of it ^.^:
So I'm an animator, making a cartoon series based around mine and his characters from Minecraft (sounds silly and all but if youd see it youd like t, its not at all what most people imagine a Minecraft series to be. In fact heres a little look at my partners character: 
Hes definitely unfinished and yet to add depth or emotion or the rest of his clothes... ANYWAYS. The idea is to have mine and his characters preparing for their 3rd year anniversary, but keeping it secret from each other. My character will be "remaking" a beautiful landmark from New Zealand (my partners dream vacation   place) because we dont have the money to actually go there. And his character will be on a search to round up a thousand bunnies (i freaking love bunnies) because bunnies are illegal where we live. And theyll each go through a series of funny events trying to hide their special gifts from each other. And upon the reveal theyll both be super happy, hug and all that gushy cute stuff and love/combine their gifts. New zealand full of cute little bunnies everywhere. And then I either want my character to propose in the video, or I want to have some kind of caption effect/type effect thats built in to the scene, asking if he'll marry me. And he whole thing will be put to The Piano Guys cover of Love Story :3. And i'd show him the video in some kind of romantic way and then we shag it all night \o/ xD
so yeah thats the basic idea and I'm really excited to do it. BUT THE QUESTION STANDS, should I? I do not want to take away the moment from him as I know he'd love to be the one to propose and it means a lot to him. Maybe I could just change the video so it ends in a celebration of our 3 years together? 
What do you all think? I need another womans opinion :D