Greenshift plugin doesn’t collect visitor’s data on your site because it doesn’t use cookie and doesn’t store IP address.
All blocks have local scripts and files which has The GNU General Public License v3.0 or similar licenses which allows to use plugin for commercial purposes.
There are two blocks (wishlist and thumbs counter in Query addon) which takes IP address of visitor, but it’s saved with random hash inside database.
Greenshift plugin has possibility to use Google fonts, but you can replace them with local versions of font via Greenshift local font loader.