I haven't used bracketed mode on the drone, but from working with HDR in the past, I might suggest just shooting in raw, then in post creating 3 or more different pictures with different exposures.
For those that are not familiar with HDR photography, the basic explanation is that you take multiple shots with different exposure levels (ie. -3,-1, +1, +3) and then combine them in software. This gives you much greater color and contrast separation.
Now the reason for shooting 1 RAW picture (DNG is the file format with the drone camera) is that you are working off of one picture. The problem with multiple shots is that when you combine these pictures if there is motion, you will get blurring in your picture. Even sitting a camera on a tripod can have this blurring issue as trees move in the breeze, or people walking. The single shot that you create multiple exposures with will eliminate this.
A program that I have used that is super easy to use to combine the pictures is Photomatix. I attached a picture I took (with nikon camera) in a park as a single RAW image and combined in Photomatix. I went heavy on the HDR here to create an artistic look. In the software, you can adjust to create a natural look or go crazy. If you want to further enhance colors, I think Lightroom is one of the best and easiest programs to use.
