[hattend]

The sight would have been unmistakable to any military person who witnessed it and there were a number in the area.

You're right. From #1:

The two National Guard pilots in their nearby helicopter now picked up the streaks high in the sky. Capt. Chris Baur saw the streak Brumley had first observed: "Almost due south, there was a hard white light, like burning pyrotechnics, in level flight. I was trying to figure out what it was. It was the wrong color for flares. It struck an object coming from the right and made it explode."

Maj. Fritz Meyer, a winner of the Distinguished Flying Cross for his service over Vietnam, saw the southbound projectile clearest. "It was definitely a rocket motor," says Meyer.

[Non-Sequitur]

That is not a description of any of the SAM missiles the navy uses. A Standard SAM is 14 1/2 feet long and would have been spitting out a stream of smoke and flame. No way that any military person could have confused it with a flare, even for a second. Any conversation among the helo pilots wouldn't have been "Gee, does that look like a flare to you?", it would have been "Holy sh*t, who shot off the missile?"

Here is an example of what a Standard RIM-67 launch looks like in the day. Tell me that someone would have missed this at night.