I'm going to send you a private message for the other stuff related to cosplaying, but I'll post links you can use to purchase cosplay-related stuff in Hong Kong here so everyone can use them if needed ~
Well, one of the most popular cosplay stores in Hong Kong:
(the actual shop is in Mongkok)
I personally buy stuff off the Mainland because the stuff there are usually more detailed, prettier (surprise surprise), more comfy, and cheaper (goes without a doubt). Problem though? Shipping (Some charge extra for Hong Kong - usually around RMB30 is a safe estimate). And you have to speak Chinese on the website.
Good luck in cosplaying!
Another place you could consider:
Laforet Excelsior Plaza Shop 109, 24-26 East Point Road Causeway Bay Hong Kong (It's right opposite Sogo)