Upper midline shift
No one really walks around with their teeth together because when you speak your teeth move up and down, and no one would ever notice that the mid lines do not line up with one another. I am more concerned as a cosmetic dentist when the upper mid line does not center with the nose and the face. I'm sorry if I bring it up and to your attention, but yours is off to the right and this would be more noticeable than your upper and lower midlines not being congruent. If it bothers you, you could correct the midline and shift it to the left and recenter it under your nose by using conventional Orthodontics. I would not recommend trying to do this midline shift using Invisalign however.
Detection of midline by layperson
studies have shown that the general public usually don't notice midline deviation when it is less than 3-4mm. An orthodontist will notice even the slightest midline discrepancy. You an be reassured that your friends will not notice it unless you point it out to them.The best way to evaluate if there is an occlusal cant is to compare it to an imaginary inter pupillary line. If the occlusal plane and the line are parallel then there is no cant (unless your eyes are asymmetric which is very rare). It's not useful to assess the cant by comparing to your lips because it is no uncommon for people to have a skewed smile caused by uneven muscle pull on each side.