If you are using device linking for screen sharing, the auto-scroll could well lag behind because the master device just can't transmit all that data -- a whole new screen image every second -- fast enough. So I don't recommend screen sharing for auto-scrolling or anything that requires constant screen updates.
If you are using device linking for remote control actions, no scroll messages are transmitted, so each device should be configured to perform its own auto-scrolling. That's why if you are seeing jitters when following remote control actions, you should just test the device that exhibits the problem on its own because I don't think it's related to the device linking.
As for all the settings ... they could be synced across devices, but many of the settings should be device-specific, so they are not. In BandHelper, some of the settings are synced across all devices owned by a given user, but not all, because you might want to use two devices for different purposes and you would need to maintain separate settings.