How heavy is it and can it be sanded? If it's really light a shit ton of spirit gum on the bottom should be enough to hold. >>9918519
I don't see why you can't just make a bodysuit and have the whole tabard sewn down, dangling part and all? Just make sure it's stretched out when you sew it on and interface the shit out of it, and use a heavier material with a zip up the back.
I definitely would not recommend using worbla for the hat. It's a waste since it wouldn't be strong enough on it's own without foam anyways. Use thick cardstock or Eva to make the hat base and cover in fabric.>>9918993
Airbrush and fabric paints