It'd be fun if you could easily access website variables live in the custom widget. So you could get the amount of players registered, or the amount of posts on the site, etc.
This would require a lot of work from [the] [any] developers, and I doubt anyone would go through with the project unless they were very interested. Even if it got completed, who knows the amount of possible security risks. You may as-well integrate a different more reliable service. The NamelessMC team made the Resources resource which publicly only allows free downloads, but on their site they support paid downloads. I assume they didn't release it due to the chance of exploitation.
You cannot do it with pages, with all the requests features, you cannot.
Pretty self explanatory. A module which allows you to create smaller individual post-like pages. Page edits can be requested. Pages can't be publicly commented on. There are page sections. All of the pages are like the current page system, but all accessible within one sidebar. The main page of the Wiki could have an index page.
This isn't the answer you are looking for; if you want basic integration, you can create a custom page and Iframe your CraftingStore shop.