I looked at this for a long time.
Look at picture #5. It is someone to the right of Fuddy, who is lying on their back with their right foot kicking up out of the water in front of Fuddy. You can see that person’s eyebrows just above the flotation vest.
The key to this is the black line on the left side of the flotation device on the person on the right side of the still. You are looking at the underside of the front of the flotation device because the person is on their back, and that right black line is the left-side breathing tube that inflates the life vest. Therefore, what you see is that person’s right leg and foot.
I think Fred Nerks was saying that that lying down person IS Fuddy. That the person you are calling Fuddy above is actually Yamamoto. The face we all see in every shot is Yamamoto not Fuddy.
I now see the inflating tube you are talking about. And Fuddy’s eyebrows! Finally. Finally I see Fuddy for the first time thanks to your explanation.
If it was a sports shoe (sneakers to my generation), it's very likely that the color of the sole was made to look "cool," and so a neon yellow is not out of the ordinary to contrast with the color on top.
-PJ