I love that you put this much thought into the maze but holy cow I'm going crazy trying to solve the riddle.
One of the keys to any Lisa riddle is that she (the character) is trying to make it unsolvable for the constraints of you (the character). As a player, you are not bound by these constraints, which is something she cannot plan for. So while an initial reading will lead to a dead end, she will also try to leave ways for her to gloat once you've set down that dead end path. At the end of the day, it may just require some out of the box thinking.