Looks like a great start to me. The only tips I can really offer are these...You might have a problem with Frogbit in that small of a tank with a HOB filter. They dont like being pushed around the surface alot and tend to bruise and melt if they are. You might get away with it, but im guessing they will slowly disappear. And the string you used to attach the moss? Its fishing line? Its horribly ugly
You can buy green cotton thread that matches the moss color and blends so you cant really even see it. Or you could wait a month or so and cut the line off as the moss should naturally attach to the rock. Great start to a nice nano tank!