Yep, all your observations reflect what I've observed with the Studio Display. As for the last point, I also have seen the display fail to wake up if it doesn't

Yep, all your observations reflect what I've observed with the Studio Display. As for the last point, I also have seen the display fail to wake up if it doesn't get a signal it likes (alternatively requiring me to simply unplug/plug-in again, reboot my machine, or change cables). Now that I have an approach that successfully works on boot and supports display sleep, I'll probably never touch it again