Thanks Janny!
Regarding King's Glades and Queen's Groves, there may be a flip-flop in the text of Stormed Fortress. Arithon visits the King's Glade in Selkwood, Shand, which would trace back to Queen Cindra s'Ahelas. Traithe warns a clan heir against visiting the Queen's Grove in Atwood, Melhalla, which would trace back to King Rondeil s'Ellestrion.
I misinterpreted the three thresholds – I assumed it referred to the different ways one could enter, rather than the three sequential thresholds one must pass over with informed consent. Makes more sense!
I'll update the Wiki accordingly with this new info.