Up on shore is a little out of my zone, but I believe pampas grass can be invasive. Native grasses, native wild flowers and pines are nice along the banks, and they do not deposit the large amounts of organic matter into the pond that deciduous trees do.
In the water, both eel grass (Vallisineria americana) and Chara can be good choices, although Chara can grow profusely in certain conditions.
If you have the proper substrate, plant directly into the soil...not into pots. I would plant water lilies in 1-4 feet of water (depending on clarity) marginals like Arrowhead, Arrow Arum, Pickerel Weed, American Water Plantain, Hardstem Bulrush, Soft Rush, Spike Rush and Water Arum in 0-1 foot of water, and shoreline species like Blue Flag Iris, Sweetflag, Sedges (Carex spp.), Milkweed, Cardinal Flower, Ironweed and Marsh Marigold along the banks.
Do not plant Cattails or Burreed on new ponds, as they can take it over, making it a monoculture, which is no fun.
