Hmmm... this fursuit seems to be a bit of a challenge, but if your really up to it.
First, draw how you're going to where it. Dosen't have to be real fancy with your human base, just as long as you have your atonomy down and you can see that it's a person, not some scribble thing you can't even tell what it is. Then, draw your chocobo costume on top of your human base (I would reconmend using different colors for this step). It looks like the human head is between the eyes to half way between the beek, the neck is the rest of the beek to the bottom of the mask, the body is from the start of the chocobo body to mid way in the chocobo body, the leg to the knees is where the body part of the chocobo costume ends, and the knees below is where the feet is (it looks like the person in this costume is really really short, or is still a kid). The wings looks like it's attached like a shield. After you make the wings attach elastic straps to it so it can fit on your wrist and that spot barely below your elbow: what i'm talking about
You might have to have you arms streched out all day, but hey. for cosplay, am i right?
After you have that drawn deside what features you want to have in it. Do you want fans in it? Do i want to see through the eyes? Write down those. These are your blueprints. The more you can go by them the better.
Then start your construction, I don't know how you would start a fursuit, but i would suggests using a helmet for the mask. After that, just keep putting foam around your head and cut it to size, add the detail, and cut holes where the eyes are so you can see. I'd hate to be blind in that thing. Keep on doing that with the rest of the costume. I'd use a duck tape dummy to help, BUT MAKE SURE THE COSTUME'S FUNCINAL!!! I can't stress that enough... Do things like cut some of the foam at the bottom of the mask in order to mover your head, and cut the foam on the body part to peices in order to move around. use this to help you understand:
I'm sorry, but I've had way too much bad experiece with funcunality.
The last thing you want to do is add the fur. You said you had experience with fursuiting, so I won't go into much detail with that. Just match it up as close as you can with the other fursuit. Looks like you'll need orange paint and sculpy for the beek, orange and white fleece for the feet, yellow plush fur that's not that long for the rest of the costume. For the eyes, just use cross stich material and markers. It should do fine.
I hoped I helped you out. I'm not good with words, plus this is just a therory. I hope every thing works out for you and can't wait to hear how it goes.