New goblin and worgen characters will indeed be eligible for Recruit-A-Friend benefits including increased experience gain and grantable levels. As we've no current plans to modify the Recruit-A-Friend program at this time or increase the level range for which the benefits apply, goblin and worgen characters (as with all other characters) will only be able to receive the in-game bonuses up to level 60.
So, to answer your questions directly:
Would the 300% xp bonus work till 60?
Would the Level Granting work till 60?
This is, of course, bearing that all requirements for those benefits are met. :)
Please keep in mind, as well, that there will be no Realm First achievements associated with leveling characters of a specific race, so this will not place goblin or worgen characters at any sort of unique advantage.