The problem with your original stocking plan is that you have too many fish that would tend to occupy the top strata of the aquarium.
I have honey gouramis in a 15g, which is fine, they stay pretty small. Make sure the females out-number the males. A trio is a good start, 1 male, 2 females. I would also stick with just one gouramis species. In addition gouramis should be added last. You will have more success when gouramis, especially the ones you want to keep, are added when the tank is quite mature, over 6 months old.
The pygmy cories are a wonderful addition. Have you considered harlequin rasboras or Espie rasboras. A small school would look stunning and provide needed activity in the middle strata of the aquarium.
A word about two pygmy cories, at least the ones I have seen in stores. C. pygmaeus is smaller and tends to school throughout the entire tank, though they do spend time in the bottom. C. habrosus is more sturdy and is more likely to stay in the bottom. Both are excellent fish.
My 15g has 4 honey gouramis (still trying to figure out if I have an extra male and if it should go back to the LFS), 6 harlequin rasboras, and 7 c. pygmaeus. I don't consider my tank over-stocked but I also have a densly planted tank and a strict weekly maintenance regimen. All these fish were also added in the course of 6 months and the tank has been running for nearly three years. I have had bad luck with people taking care of my tank over the holidays, and children dumping food in my tank, resulting in wiped out tanks.

If the extra gouramis is male, then it goes back to the LFS, if it's a female, then I see no harm in keeping it.
I think Wolf's advice is great. Never add everything at once and always pay attention when stocking a tank to where the fish are going to be. A balance in the three stratas (top, middle, bottome) should be observed. If you can look at your tank and see all your fish, it may be too crowded. It takes me about 15 minutes to find all of mine.

Of course, if you have a large tank with big fish, it may be possible to find all your fish in a glance, but I don't keep those kind of fish.
I also have a trio of T. pumilus, which is the same genus as sparkling gouramis. In fact, they were labled sparkling gouramis at the LFS, but Linke and other authors refer to pumilus as the croaking gouramis. But who knows? Books are not always right. They are extremely hard to sex at the LFS. You need a flashlight and you need to know what ovaries look like in a fish. I am lucky, I think I got 1 male and 2 females. They are in a 10g, which could use a middle/bottom dwelling fish. Enough about me and my problems. Good luck with your fish.
