I would say not to try it. Gold gouramies, like other three-spot color morphs, tend to be highly aggressive fish when it comes to dealing with other gouramies. If your tank is large enough, you could try adding 2 mroe females but they'd have to be the same size as the existing fish and you should re-arange the tank somewhat just before adding them. Don't try to add a male - that will lead to problems for your other community fish if they try to breed. Also, males are a lot more territorial than females and do better kept alone if in a community setting.
As for mixing with other species, again, I wouldn't suggest this in the case of three-spots due to their sometimes unpredictable nature.