If you're planning on playing together, go for classes that will make it easier to run the dungeons together. Don't both play healers or tanks, and make sure you pick classes that start in the same area. Otherwise it shouldn't really matter.
Have fun! Questing with friends/loved ones is always a blast, and as the others have said Gilgamesh or Balmung would both suit your needs.
Have fun! Questing with friends/loved ones is always a blast, and as the others have said Gilgamesh or Balmung would both suit your needs.