Such a group assault on one small detail - we might even get somewhere.
Below are my newest results. BTW - I'm very glad that you give checkable references, but I would prefer if you gave the dates also. And of course iconographic evidence (from old illustrations) is stronger than photographs of (potentially restored) castles.
By now I'm firmly in favour of the "fantasy castle" hypothesis. Because: - almost all swallow tail castles (with two exceptions) have square towers, not round ones,
- none (none!) of the castles with swallow tail towers also has "lightning conductor" style towers.