Awesome! Glad you enjoyed it.
You're right about n15 being covered, but there's another way to find it. It's possible you found it without realizing it, because it sorta breaks an implied rule:
[rot13.no] Nygubhtu a15 svgf gur pngrtbel, vg vf ab zber bs n jbeq guna Bgntrqnhtary.
You may want to write down a proper word list for puzzle 12, with the Divider Line and everything.