You can always try! Two pair of the Gouramis is better than one Betta fish. Just keep a close watch to see what happens. Of course, you must always provide enough plants, grass and anything like decors, rocks or driftwood for the shrimps.
1 male and 2 or 3 females will be fine in that tank. I was just a bit worried that a lot of people have tiny shrimp tanks, less than 20 litres!
You may find that your local shops price their dwarf gouramis per pair. In this situation with apistogrammas, I asked if they'd sell me an extra female and they agreed. The worst they can say is no.