The original creatures convert to AC 16 (lesser) and 20 (greater), and don't appear to have any armor (simply robes). So maybe a deflection or profane bonus would be appropriate?
Sounds right, but does it boost the AC enough in this case? Should we swap some ability scores around? Swapping Con for Cha gives us an additional point of AC. Speaking of Con, that needs to be changed to - in the wyrd version.
I think we should switch to leopard for the greater wyrd's companion (also saves us having to stat anything out). Humanoid (elf) works for the second favored enemy.