To your third point, is this a setting somewhere? I tested before I posted w/ 4 Brave windows, but they stay in the same order.

Makes sense, since cmd+~ immediately switches on key down to the next window; cmd+tab (like alt+tab in Win) lets you keep the selection open and choose an out-of-order app, which alters the MRU. How would you do that here? The only way I've affected it is creating/killing windows at points in the cycle. Using cmd+shift+~ for me just goes backward in the same static order.