Sharing app content between portals using 2Sxc

I need to design a content system similar to the news article 2sxc application. However, in my situation I have a primary subdomain and multiple secondary subdomains each of which is a portal in a single install of DNN. I need the primary to be able to selectively share articles with the secondary subdomains. I also need the secondary subdomains to be able to have their own articles. I have explored creating a ghost content type on the secondary sites, but this doesn't seem to share the content. I have used the visual query designer with an App Data Source to pull data from the zone and app of the primary. Using this, I can pull the needed article data, however, it also pulls lots of meta data like the name of each field on the content type etc. So I assumed I could filter this stream by content type, but when I do that it removes all items in the stream. Additionally, I have tried using razor code to get the correct data, but have been unsuccessful. So:

1. What is the best way to accomplish sharing the articles as described?
2. What am I missing on the visual query designer that is causing it to filter all results when filtering by type?

Thanks

If I understand you correctly, for 2, you are using the App Datasource. In the docs (linked), have a look at the first screenshot and the note above it. By renaming the streams coming out of the source, you automatically filter on the CT.

And for 1, I do agree that using Queries seems like a great choice.