Tweet Wheel Pro is licensed for one year at a time. After that you may renew your license to continue updates and support.
Yes it will, and this is perfectly legal.
No at this time.
Not at this time.
No, you should only activate your license on your live site. You may still install the plugin on your test server and use it without an active license.
When at the checkout, enter your current license key or visit the Licenses page within your account.