I'd recommend the following:

  • Pally + 4x Shaman - It's much easier than any 3-class setup and is viable for any lvl 70 or Heroic instance
  • Level all 5 up to 30, then swap out the Pally for either the Lock or the Hunter, then quest boost to 60.
  • Gift the Pally from 30-60 and you're all set. All in all, it should only take you 2-3 days /played if you avoid the "bad" drop quests
  • If you want to add a Druid option, then your original description makes sense, but will take about twice as long (guessing 4-5 days /played)