Yeah, I know that Google advices "no mouse events" in Chromecast. But who cares?
Mouse pointer position is sent with standard GCast sendMessage.
MouseEnter and MouseLeave events are simulated with document.elementFromPoint function.
Click and other pointer events can also be triggered.
Also remember, Chromecast does not have css pointer events, so you have no :hover etc. subclasses. You can use .hover classes instead.
For instructions how to run this example follow the Google Cast API documentation.
Good luck.