Our site has different type of articles. Based on the type selected, the fields displayed to the user are varied. The ask is to create a multi-step form and include type field on step 1. Based on the type, subsequent steps and fields included in those steps need to vary.
An important ask is that they need the ability to change the type of the article after it has been created. So on day 1 they might create an article with type "single page" but later change it to "multi page" (Multi-page article has all fields in single page plus additional fields).
Another important requirement: An article could have multiple (0 or many) sections and each section could have multiple subsections. What is the best way to model the content type? Create content type Section and Subsection and then use node references (article will have a nod reference to section; section will have a node reference to subsection)? Using node references, can one to many relationship be implemented?