The third one looks like Eleocharis acicularis or something close.
The fourth one looks exactly like Hemianthus micranthemoides, growing emmersed.
The first two, however, are puzzling. The first one looks like a Cryptocoryne to me (by the way, it should not be planted so deeply), but I am positive that is not it. The second one looks like a species of Hygrophila.
Carlos