What's the best way to create a grid layout using bootstrap, or see link below http://v4-alpha.getbootstrap.com/examples/carousel/ displaying three different headings, should i use
wp-query or, sidebars?
In my opinion, you should use wp-query. Using a sidebar for this purpose will yield problems in the long term.
SEO: Sidebars are taken as "aside" content, which is considered less relevant content by search engines.
Editor: The editors for the sidebars are much worse than post editors.
Reliability: Any change to containers added in function will reset all content and setup.
Scalability: More functions available to work with on post.