And extending Customer Privacy Data module to contact form is also very easy. Hook needed in contact-form tpl and additional override file ContactController.php in folder /override/controllers/front/
I'm not yet using the TB on live shop, but might use it very soon.
Have just upgraded to clean 1.6.1.18 and have applied the Contact-form Customer Privacy data, so it should also work on Thirtybees install.
Regarding the cookies.
If the only cookie your shop is using is the prestashop session cookie, than you can set it's expiration time to 0 and than it meets the GDRP requirements as it becomes true session cookie which expires when browser closes. In this case Cookie popup is not needed. Sure visitors will loose their cart everytime they close the browser, but make sure you enable "Re-display cart on login" for registered customers.