So I think the Cairn Wight's good to go or pretty close to it and it sounds like you're closing in on completing the Cairn Shadowraith.
So I guess it's back to the
Dodkong.
It's been a while since I read the original 3E entries, sparse as they where, but from what I remember the original Dodkong was a Third Edition D&D Stone Giant Lich 10th-level sorcerer, which
technically is in breech of the Lich template as that can only be applied to humanoids. That's no big deal though. It's easy enough to just ignore that restriction and apply the template to a Stone Giant.
The salient point is that it's got all the abilities of a lich, like a paralyzing touch, various immunities, fear aura and the ability to reconstruct itself after being destroyed as long as its phylactery is intact. Did the crown acted as its phylactery?
Anyhow, versions of those abilities are possessed by the 5E incarnation of the
Lich, so shouldn't the Dodkong have some of them?
Such as:
Damage Resistances cold, lightning, necrotic
Damage Immunities poison; bludgeoning, piercing, and slashing from nonmagical attacks
Condition Immunities charmed, exhaustion, frightened, paralyzed, poisoned
As well as "borrowing" some of the 5E Lich's Traits and Actions or using them as inspiration for its own Actions.
For example, instead of
Paralyzing Touch, you could have the Dodkong's
Death Grip cause paralysis as well as exhaustion, maybe with a tweak to the name to indicate it's a different ability.
The 5E Lich has
Legendary Action options that look quite appropriate for the Dodkong:
Frightening Gaze and
Disrupt Life.
Also, standard liches aren't bothered by daylight so maybe ditch the
Sunlight Sensitivity?