[Iron Munro]

It looks like the big black man to Hillary's left in your first photo is the same man seen in these other photos.

Is he a doctor, perhaps?

Notice that in the middle photo it looks as if he is carrying some sort of injection needle or epi-pen.

Compare the pin in the man's lapel in these photos.

It looks like the same man even though he is wearing glasses in the photo on the left

[TigersEye]

The Secret Service lapel pin?

[OKSooner]

In the five pitchas you posted, the guy in the upper left one, on her left, is a different guy. He's not the needle/flashlight man. Check it out, he's portly but fit-looking, I'd describe him like Charles Barkley 20 years ago. Also his hairline is different.

The other guy, people around here have taken to calling him Bart, (I prefer Fat Face myself), is quite chubby.

I have no information about who the first guy is, but he appears to be more legitimate than Bart/Fat Face and I would assume he's Secret Service. But again I have no information about him.