A "Page Type" is more of a template/layout for a page. A couple examples of a page type might be "Full", "Right Sidebar", "Three Column", etc. It's basically how you determine what content areas will be available on that specific page.

Page Properties are typically things built into the page object behind the scenes. These include things like publish date/time, page title, and page description.

Page Attributes are more or less the same as page properties except these are often where you'll find customized "properties" as well. Often times you'll find a lot of SEO stuff in here, but it would be feasible to add custom attributes like "Page Background Color", to this and then build logic into c5 to use those custom attributes in whatever way you so desire.