1: Newest Thumbs is available on the gallery index page of the pro version. There is an example
here.
2: Yes, you can upload more than one file at a time with the pro version. There is a screenshot of the ACP options
here.
3: The pro license is a "forever use" license as long as you abide by the license agreement. You only need to renew if you want support and download access after the year is over.