My assessment of the jump and footwear is this:
There are three basic points of view that are expressed by Cooper aficionados:
1. Those folks who view Cooper as somebody like themselves. They say, I would have died if I jumped without jump boots, so Cooper must have died. Jerry Thomas is the leading advocate for this perspective.
2. The journalistic point of view, which holds that most skydivers feel that Cooper could have made the jump successfully because they know of many instances in their skydiving careers where people have jumped successfully naked, in flip-flops, sandals, loafers, sneakers, in the snow, in the rain, into the jungle, into thick forests. Therefore, footwear is not an issue.
3. The third group doesn't like #2 for a variety of personal reasons, such as they know of a skydiver who thinks Cooper was a whuffo and died in the jump, or don't want Cooper to have succeeded because they want to support other agendas, such as the FBI would never lie to them.
There are many facets of Norjak that subscribe to these dynamics, and you can substitute shoes of any number of aspects of the skyjacking and get the same type of answers. Such as: Cooper was underdressed, it was too cold, the wind chill was too severe, he picked the wrong chute, etc.
Bottom Line: Why are the shoes an issue for you?