The first one is shaped like a tern, but I'd never seen them heckling an osprey before. But then again, there are more terns around lately.
We watched that last one hunting small bugs on (and crapping all over) our windshield for hours. In the full-res photo, you can make out fine details on his legs, feet and abdomen. Very cool. Not sure who would have won the fight if I went out there to swat him. He flew away sometime after we got underway. I think I heard him calling the tower for clearance to take off.
I believe around Apalachicola those are called "Guard Flies" a couple of years ago a guy there told me not to shoo them away, they will keep the smaller biting flies away.
No idea if it is true or not or if maybe that guy is the only preson who calls them that?