If you like bigger barbs the dawkinsia recommendations are great. I like rohani, but if I could ever find them at a good price I would keep assimilus. If you like medium sized barbs red pandas are really sharp. I had drape fin barbs once and they were awesome. I will definitely keep them again if I see them. Snakeskins would work well in there also. While they are extremely common don't knock a rosy barb. Big schools of rosys are beautiful.
As for the gourami I feel the snakeskin gourami is fine in a 75 depending on what your waterflow will be like I would toss a pair in there. (Everyone is entitled to an opinion on that.) If you haven't bred gouramis before they are pretty fun, and the fry will mostly get eaten by your barbs.