In the second set of birds from post 18, there are at least two 1 cy White-Winged Terns among them.
Its the left bird on the horizontal bar and the small preening bird just right front of the center sitting on the pond.
Both show the right head pattern with much white above and behind eye, small all dark bill and a dark brownish, nearly black saddle of retainend juvenile feathers.
Other birds of the post 18 are Whiskered Terns or are unidable to me. I am not sure about the two preening birds on the far left corner just before the vertical bar. They might also be White-Winged Terns by head pattern, but they are not easy judged (more pictures or other comments, so I can learn?)
If I had to put a name on all birds from post 18, I would say, Whiskered Terns and 2-4 White Winged Terns.
Hi, Alexander: Today, I went to the same place and managed to get some photos when the terns flied closer. I am quite sure of those whiskered terns already. however the following 3 images for your final confirmation. Thank you so much!