Also, as I noted in the Rovelight thread, having E-TTL on in any way will make hypersync not work with the 622 + Rovelight 600 combo. If your camera body (or master speedlite/controller) is making the 622 go into E-TTL wireless mode, the timing is thrown off and hypersync with PC-cord-connected strobes will not work. What you've discovered with the YN600ex-rt I think is a clue to your other problem with not getting the Rovelight to work alongside the speedlites at HSS shutter speeds.
Off camera YN600ex-rt and Canon 600ex-rt both can't be changed from E-TTL to manual if they are wireless slaves. As soon as the camera body signals them again, they will flip right back to E-TTL if E-TTL flash mode is what is set on the master, either through the master flash/controller itself, or through the camera body's External Speedlite Control menu settings.
When you have an off-camera 600ex-rt set as a SLAVE, the master will override the mode (E-TTL, M, Multi) and the Power Level, and the Sync setting (HSS/1st/2nd) as soon as you take the next photo! Only things like zoom and custom functions will stick, nothing that the master sends values for.