You can translate xF into whatever language you want.
On these forums you can have a look here: http://xenforo.com/community/forums/languages
A Greek language pack is currently not available there. This means you either have to create it by your own or find someone doing it for you, I guess.
Forum Views, I'm not sure on, but the rest will most definitely get imported over. With proper redirects set up (301 Permanently Moved), search engines will gradually update their indexes to point to the next XenForo installation.