Absolutely! All future updates will be free after you have purchased a license for the theme. You can manually update the theme by re-downloading it from Themeforest or by using our auto-update tool.
Yes, you most definitely can. However, it also goes back to whether your reason abides by Themeforest’s refund policy which can be found here
Envato does a better explanation between the difference, so you can find the link here
As much as we would like this to be a thing, unfortunately we got bills to pay at the end of the month. So we restrict the use of a single license for multiple websites. If you need another license, you will have to buy another copy of the theme.