Egg used for breaded poultry added to other parts of the dish. Is this a health hazard?
As long as the egg is cooked to the doneness necessary to safely cook the pork, this is a fine process.

Someone will surely say that if the egg sits out it will be unsafe. In fact, you have a window of several hours, especially if it was cold to start. 

The scenario of putting the egg in while the rice is in the 'Hold' phase DOES sound a little risky, though, as that stage probably does not go above 140 F

If adding to the rice do it with several minutes of full heat still to come, or scramble the egg in the frying pan and add it like that.