Eel grass -
YESWidgeon Grass - maybe; waterfowl benefit - but could be risky.
Parrotfeather - maybe; actually an emergent specie (portions of the plant grow both submerged and above the surface). Personally, I'd avoid it.
NO (IMO) to the others.
Oh, and why would you consider introducing invasive-exotic and Fed-prohibited plants (EWM & Hydrilla)? Your local chemical salesman might appreciate that decision - but you would definitely regret it.
Also, the pond's design (perimeter depth-drop) is a huge factor in deciding which, if any, submerged plants to introduce.
