While it's great that you want to put them in a pond in the summer, you've got a lot of work on your hands. Comet goldfish grow fast and are very high waste producers. You should be doing 50% water changes every other day to keep up with the water quality. Over-filtering can only handle so much and it won't remove nitrate. You are also going to want to drop the temp down around 60F if you can. At the very least, don't heat the tank as heat speeds up their metabolism and will make more mess for you. Another way to cut down on the waste is to only feed them every other day.
As for their health, I thought I saw some ich spots on the brown one. It could just be reflection from the glass, but you're going to want to watch for flashing and other signs of distress. The one in the second picture has some clamped fins, but it could just be from being confined and having a flash in his face. Either way, watch them for signs of laboured breathing and flashing. When you are overstocking a tank like this, any disease can be deadly.
The only way to tell goldfish gender is when they are spawning. Yours are too young to spawn. Next spring you might see some spawning behaviour in your pond. The females will look much more plump from above as they are filled with eggs and the males will be chasing the females and nosing at her vent. So for now, just kinda name them whatever you feel like.
Do you already have a pond or are you going to build one?