This is a great thread and very informative! I was looking to start a Druid as my first character, having loved the class in other games, and wanted to pair it with a Warden so I had a pet.
If you're looking to heal as a Druid, I would suggest having a Scout or Mage as a third, since Druid/Warden isn't that good of a healer. I haven't really tried out Druid/Warden much, so I can't offer much advice on it.
I will say, that you won't be able to use the Warden's pet on your Druid, since it's a Warden-only skill. However, if you go Warden/Druid, you'll be able to use your pet and have heals.