“The two papers I cited demonstrate that opening the thigh-torso angle shifts the emphasis towards the hips.”
You asserted lower heels during the pedal stroke engages the glutes. So the two papers you site actually refute that claim. One paper held the ankle static & the other paper explicitly stated there was no difference with ankle angle. So there you go.
If you mean to imply you should change the title of this thread to ‘Increase hip angle to engage that joint more’ …well…your hand is on the keyboard.
But that still is an assertion that is separate from the Coyle research linked in the original post. They make no assertions regarding which sort of pedal stroke engages the glutes or hips more or less. So stop trying to place your own albatross round their neck. 