You need to achieve first class honours to be awarded a GPA 7, not just an honours degree. After
sal123 missed out on an offer today it also seems that you need to achieve a first class honours equivalent to over 85+ rather than 80+, otherwise you won’t be awarded a 7.0.
Yes, you’ll be applying to the undergraduate degree and you’re allowed to do this. Technically you can complete as many undergraduate degrees as you would like to, it’s just that some undergraduate medicine and dentistry courses restrict applications to school-leavers; Griffith is not one of the unis that does this for dentistry.