Without reading closely.....................my guess is the middle two are switchers. But, now that I read the text more closely, they are the same supply, but with different cables. I'll pass on guessing which cable is the worst. The baffling part is what is causing the cyclical pattern.
That leaves 2...................so, I am going to guess the truly dreadful one is the USB hub.
That means the Meanwell is the quietest. Which I find...................uh.............. ......reluctant to believe.
Can't easily explain this, especially in layman's terms, but I can tell you a certain very popular brand of 5 V wall wart really screws with some of my SW radio stuff. It creates 60 Hz sidebands on the oscillator. So, we try to avoid SMPS at all costs, which is almost impossible. The SMPS on our computer monitor makes 60 Hz crap on our phase noise plots. Depending on its physical location, wrt to the phase noise rig and what is being tested. Don't ask how much time was lost trying to solve that one.