As well as adding your own custom categories you can add an automated category that shows products based on what option you choose. You can also use this to auto-populate categories for brands, suppliers, manufacturer, or your extra fields.
You can add information to a category area that will appear as an information tab on all products in the category (Additional Information Category Wide)
Or do you need to create relationships between your products, and the make/model/type of products where they can be applied? eg Car automotive industry, some parts fit many different types of cars. Yes you can
In the ecommerce > Display Options area you can check a box 'Show Product Sorting Dropdown' to show a product sorting option on the Product list page. Sorting can also be changed globally and per category.
by default hiding a category does not hide the products within it. By checking the cascade security options found in the Category settings area the security setting you choose for the categories can be applied to the subcategories and products within.