I am worried about your GH. You have very little calcium and magnesium for the plants. In south TX my KH is 14 also, from well water, but my GH is 14. With a GH of 2, you should be adding calcium and magnesium.
I am also looking to stock with the same fish: blue fins, mosquitos, and sail fins. I am still cycling the tank but most plants are growing well.
I am trying to find a salifert fresh water potassium test kit. When I get it I’ll be able to determine if my K is enough I just watched a video where the person’s java fern was sucking up all the K in her tank. Once she added enough K, the other plants did well.
its almost sounds like you have an inline water softener that is removing your Ca and Mg. Make sure you push the bypass valve on the water softener before filling your tank.