Dragonettes I would steer away from until you have a mature tank and a reliable food source for them lots of beginners get them because they are colourful but then unwittingly kill them because they are specialized eaters.
Dottybacks are notorious for being aggressive however as you have such a large tank they will most likely have their own area that will be theirs and might leave your other fish alone
Have you considered Cardinal fish, gobies, wrasses?
As to coral I suggest staying away from Zenia, Anthelias, Kenya trees they all look pretty but can quickly overtake your tank and all three are virtually bomb proof they can live through stuff that can kill everything else
Frogspawn and hammer coral are easy to care for and can add colour to your tank but need space as they can kill other coral with their tentacles
I also suggest checking out
www.liveaquaria.com if you have already not done so it's a very good site to visit and even experienced reefers visit it it's basically the ABC's of fish, coral, inverts