The answer to "Will they restock product X?" and "Will product X be available in my region?"
Nobody really knows. Anyone who does isn't allowed to tell you.
One could research at restocking history by searching the subreddit and archives of the website on archive.org or archive.today. A historical pattern doesn't guarantee future events, however.
One could subscribe to email newsletters and social media channels for the latest public announcements for your region.
One could research how easy it is to buy a product from Japan at MSRP to determine whether there is still ample stock available in general.
The best thing you can do contribute to a restock is to, every once in a while, search for the out-of-stock product on a search engine or the official store website and click on the product to add to its traffic.
Actually, the best thing you can do is get a job in the supply chain of these products.
Remember also that restocks are sometimes re-releases with a different production process that may result in significant differences.
May the odds be in your favor, and may the mod team add the regex 'restock.*\?' to their automoderator configuration.