There is no proof yet without good close up pictures that the sunfish type fish in your pond are green sunfish. However IMO and experience the chance of them being GSF is 99.9%. jpsdad says don't stock small predator fish in with the GSF is because the predators that you stock has to be able to immediately eat the smallest fish as food to survive and grow. Numerous GSF are aggressive feeders and competitors and they will out compete for food newly stocked fingerling bass who then do not survive. Usually for a bass predator to eat a sunfish, the predator needs to be at least 3X longer than the sunfish. If it were my 1/4 acre GFS infested pond I would be stocking asap 10-16 LMB that were 8"-10" long.
Here's a picture of what I found. I used a pool net to scoop them up.
