Blocks an access to a website blog from websites, which have not been specified as allowed for this blog
hide product per customer, invisible product on web shop per login user, limited product for guest or any user user, website product filter
simplify the ordering process for wholesales, business to business sites, or any customer who would like to add multiple variants of the same product in cart at once.
If you want to display a current status of product stock in your website, So you can do easily by using Stock Information in Shop page module.
Yes, you can set up multi-company, multi-website, multi-theme, multi-eCommerce on a single database!