Hun, no, like I said, it's NOT WiFi. Yes, just go into Mystery Gift and download it. When you are in the store. It will show up. It really isn't that complicated.
Did you actually click on the link I sent you? It says POKEMON CENTERS and POKEMON STORES in Japan, so yes, all of them.
It's a regular local download event, so if you have any more questions I'm pretty sure you can Google.