The larger lily-type of plant is called Nuphar (aka spadderdock, as Bill mentioned), while the smaller lily-type plant is watershield; and the small elevated circular-leafed plant is pennywort (aka "dollar weed" when it grows on land).
MS is a cotton-producing state, so I'll presume that 2,4-D is "regulated" there as it is in TX (whereas an applicators license is required to purchase 2,4-D). If that's the case, do you have a pesticide applicators license?
