I currently have mixed gouramis in my 55g.
2 moonlight(m+f)
2 golden(m+f)
1 platinum(f) &
1 blue(f)
2 Pearl(not certain of gender, but they look identical)
The moonlights are adults, but the rest are young.
They all get along fine, currently.
Prior to these young ones, I had these same moonlights in the same tank with 4 other opalines with which they grew up and lived for over two years. The male moonlight is a skunk. He's bossy but has never hurt anyone. The others which I expected to be more aggressive, were not.
I encouraged my sister to get oplaines for her tank. She got one bossy female... She pushes the rest of the tank around includeing the 8 inch pleco that used to live in my 55. That poor guy can't get a break(see below). I've recommended that she take the overly agressive fish back to the store. She refused, so we'll see how that is gonna play out.
Now my dwarfs were a different story.
I had a Flame Dwarf male that would chew on my pleco(same pleco my sister now has), a fish 8 inches larger. He killed three of my 5 dwarfs.
I blamed the moonlight at first who was still young but by far the biggest, until I saw the dwarf giving violent chase. He went into his own 10 gallon tank... I tried to get him tank mates but he never liked any of them. he lived about 8 months longer. I had a couple dwarfs left over from the slaughter that lived happily in the 55 for almost 2 years with the opalines and the moonlights. I don't keep dwarfs any longer, so that is the extent of my experience.
In the end, it will depend on the fish.
How big is your tank? The bigger the tank the more likely your chance of success.