The link above may help you with the GouramI species. I wouldn't recommend more than 1 Blue GouramI per tank. They will fight other males and they will fight females after spawning.
Keep in mind that your Mollies are going to spawn unless you get all males. I'm not certain all males would be a good idea so let's get more responses.
Great advice from Ken about not having more than 1 GouramI in one tank. About what Ken said, I'd suggest getting females because having that many males can maybe start a fight from my experience. So maybe 1 GouramI and 10 Mollies will look nice. IMO, how about getting some cories? You could make your stocking list look like 1 Gourami, 6-8 Mollies and 6 Cories? Albino Cories are quite cute IMO.
Most people will tell you only 1 gouramI per tank. However, if you can find Pearl gourami's, it might be possible to have more than 1. Overall, they are known for being a lot less aggressive than others.
Unfortunately, I am assuming you have 3-spot gouramis (eye, spot in middle of fish, and one towards tail). They are known for being the most aggressive.
If you are forced to keep the two blue gouramis, in my experience, if you have some floating plants, they do a lot better since they won't be able to see each other as much, etc. If nothing else, I would maybe try some water sprite attached to a suction cup at the top middle of your tank. That would effectively split your tank in two for gouramI purposes.
Last, in my own personal experience, young gouramis tend to not fight as much. So, if you keep them, you can always plan on putting one in another tank later on or maybe even trading for another fish at your local fish club, etc. They're beautiful fish, I would imagine it would be easy to trade them.
LFS should accept an exchange? They were probably thinking you'd want a pair for mating reasons. But in this case, you have other tank mates with the Gouramies so it's a different story. Try to explain it to them, I'm sure if they're kind enough, they'll at least accept an exchange. Best of luck!