Question 1: No, currently TubePress only supports Vimeo and YouTube Video feeds. Sorry for the inconvenience.
Question 2: When using TubePress, it is possible to remove the "related videos" that shows at the end of YouTube video's. An example of the shortcode is below:
Question 3: Wordpress is not a web hosting company, Wordpress is what is called a CMS (Content Management System). It allows you to easily create, edit, move and delete pages, sections and even your entire website. Please take a look at either http://wordpress.org/ or https://en.wikipedia.../wiki/WordPress for more information on WordPress.