Hmmm...I wouldn't know another really, really helpful forum besides the ones you mentioned, hehe, I'd wait for cosplay.com. So when it comes to the hat the best things I can give you are a pic and some links XD The hat I think is intentionally made to look handmade by a beginner or something, it's very loosely knitted, and with bulky material, I can't think of anything that would closely resemble it at all, sorry hun
If you know anyone who can knit, I'd ask them. Headbands are really easy to make in the first place.
Close-up of hat 
Customized Pins At Zazzle.com
zazzle is cheap
And star dangle earrings are everywhere!
I'm sorry I can't help you more, silly Ayabie and their fashion accessories >_<