Hmm, firstly, from the picture you posted the plants in the middle of the tank don't appear to be aquatic. I'm assuming you probably bought them from somewhere like petsmart?
And it's a little hard for me to be sure from the picture, but the rest look like swords, anubias, microsword, and jungle vals, which your tank parameters should be ok for. But it seems from the pictures that you have your anubias planted in the substrate with the rhizome (the bit where the leaves and roots both come from) buried. You need to raise the rhizome and just bury the roots with that plant, else it'll rot. And it'd be even happier attached to some driftwood or rock.
Beyond that the browning could just be the plants acclimating to your tank, a deficiency in some area, or even just diatoms settling on the leaves. If you had a clear picture it would be a lot easier to say.