1 looks like a Common Tern to me.
The other 3 I think are Little Terns.
I can see why Fred might think Lesser Crested for 3 but is it just a Little Tern taken at an unfortunate angle? It looks very like the bird in 4. Zooming in reveals what looks like orange/pink feet. I'm far from certain though.
[Not Fred...] Tern 3's cap pattern extends down to the bill base, and I see no hint of a white forehead. Bill shape appears longer to me too, and colour more orange. I can't see the feet very well but I think could well be the dull pink/red of lesser crested as much as orange of little. I still don't think this is little tern...
Lesser Crested Tern also has a heavy dark trailing edge to the primaries, which this bird lacks. I can certainly see the resemblance to LCT, but I think we are being tricked by the angle of view, making it hard to see some of the features of Little Tern. It doesn't help that it lacks a black tip to the bill, but then the one in pic 4 doesn't either.
Little Tern for me, could even be the same bird as pic 4?