They can become pretty dominant. I also prefer to add them after the six month mark. The reason for this is that they love to eat algae off the rocks. A new tank does not have this.
Hmm. Wonder what I should do then. I have a flame in QT that needs to go into the display soon, but it'll be the first fish. Not sure I can add the other fish from my list fist.
Most dwarfs are pretty aggressive to new additions (( though there are a few that are pretty passive )), but like was mentioned above, the bigger concern is the tank being mature enough. I currently have 6 dwarfs and have been keeping them for decades, the most helpful thing with keeping them is having lots of mature live rock for them to graze upon all day long.