Hello, welcome to the community!
I personally do not as I don’t have this hardware. However, it does support multiple hubs.
I can’t tell you the delay of the hardware, but I can tell you that services are executed like a waterfall. This will add a minor delay (in microseconds) between each service. In your case, each service would be ‘turning on a scene’.
From what i’ve seen on the forums, the general answer appears to be ‘yes’. These devices come through as a sensor and you create automations based on the sensors state. These automations can do anything, like turn on a scene. ref Lutron Pico configuration example - #5 by broox