Fist, Nice costumes Mistys Wig could be better but the rest is fine.
The idea to use this place is good, but if you would go a little more deeper into your camera settings you could do much better:
-Try a lower angle.
Set the camera to a faster shutter-speed between 1/200 up to 1/500 your even faster, that would freeze the water which can look really impressive.
-use a reflector to lighten up there faces. It is always handy to have one, folding reflectors you can get for under 20 US$ they fit in every backpack. If buying one is to expensive you can find many tutorials if you search for DIY reflector on youtube, it's ease to make one yourself and it's cheap.
Also this image would be perfect for a close up, such nice faces close together looks really adorable