I don't think this will be related to the article in Google News or not.

Google News means that website following the guideline. If the other websites are doing a good job with PR. They may still rank higher.

You shouldn't be able to post onto a Google News Site, they are for Current News articles and written by authors from the News Site, if you able to submit articles to the site, they would be quickly removed from the Google News Network.

Google sometimes displays what they call "blended results". That is when a result from their news approved sites is blended in with the regular search engine results. Aside from that, Google maintains to its news publishers that your status will not give your content any special advantages over regular sites when it comes to the search results.

The simple answer to your question is yes AND no. If you get your article published on a Gnews site, you will normally get what we call a news box on the first page of the web search results, but it will generally be below the fold and most often it will be the 10th result. From time to time you can get the box at the top of the search results, but big G seems to have a gauge of what people are writing about and the news box only tends to stay at the top of the serps when there is legit current news on a subject.

Surly it will help in getting good ranking in google search results. If your article get approval from google it will be helpful in getting ranking. Similarly press releases are very much related to news of website and i remember a SEO in which press release help in getting good ranking.

So i think any article related to news will also help in getting ranking on google search results.

yeah,surely it can come to top results. i have seen some articles on google news approved sites coming on the top.

yes but use keywords that are most searched