Hi Edward. Rice uses 3rd person omniscient in Prince Lestat, which allows her narrator to know all the thoughts and feelings of her characters. In keeping with your observation, she limits her narrator to one character's POV per chapter, only moving from mind to mind at the transitions.
Some writers do "head-hop," however--what you describe as "jumping from one person's internal dialogue to another in the same scene." Here's an example from Hemingway's Old Man and the Sea:
He was an old man who fished alone in a skiff in the Gulf Stream and he had gone eighty-four days now without taking a fish.
It made the boy sad to see the old man come in each day with his skiff empty and he always went down to help him carry either the coiled lines or the gaff and harpoon and the sail that was furled around the mast.
The old man had taught the boy to fish and the boy loved him.
Others, of the older fisherman, looked at him and were sad. But they did not show it and they spoke politely about the current and the depths they had drifted their lines at and the steady good weather and of what they had seen.
“Yes,” the old man said. He was holding his glass and thinking of man years ago."
While I think that "head-hopping" is difficult to master and novice writers should stick to more conventional POVs, my suggestion is that Rice is free to head-hop if she chooses. She doesn't, but the option is there.
There are, of course, many useful rules of thumb when it comes to writing fiction, but our most revered writers often make a habit of breaking them. That's not to say the rules aren't useful to most, but it does indicate that the only ironclad injunction we have as writers is to be creative. That rule applies at the most fundamental levels, like selecting a POV.
Thanks for responding, Edward!