Does Uranus ever tilt enough so that its north pole is actually on the northern side of its orbital plane, so that it is sometimes retrograde, and other times not?
The angle between polar axis and orbital axis by about 82 deg. North pole is northern to the orbital plane. It is facing Sun, for about half orbital period of 42 years, Retrograde motion is unlikely.
There are some references like
indicating that one Pole is continuously facing Sun.
Anyway, night for North Pole for about 42/84 years does not indicate any retrograde motion.