Features of jQuery script are on homepage of slider, features of WordPress plugin can be found on WordPress version page.
Yes, you can add as many sliders as you need to one page, with different skins, options etc.
No, and there won't be such option. Playing video without user action is not very good practice, that's why it's not present in my plugins. However, you may use slider JavaScript API to implement this feature by yourself.
No, you can get all updates of RoyalSlider completely for free.
RoyalSlider is built in best practises of WordPress plugins and works with absolutely any theme.
Absolutely not, RoyalSlider caches all sliders using WordPress Transients API.
Make sure that you unzipped archive that you downloaded from CodeCanyon, inside you'll find readme file.
Contact me with detailed explanation of your project and where you want to use slider. If I agree with the way how the product will be redistributed and how it looks like - I will provide written permission.
For each website new regular license should be bought. Read more about regular license on CodeCanyon.
No, it's still for single end product, please refer to Envato licensing FAQ.