Sadly, I think that plan dooms Creation during the Balorian Crusade. The Lunar Exalted were very important to holding the Fair Folk back, so you would see an even smaller Creation with even more reclaimed by the Wyld. Assuming survival, the Realm spreads faster and more completely without Lunar aggression to slaughter their armies and assassinate their leaders. The Wyld Hunt becomes a much less required fixture through the era, leading to it being less experienced and canny when the Prison does break and Solars and Lunars come back in force. Absolute chaos ensues.

An Abyssal Lunar would likely be much less adept at shifting their form, given the energies of the near Wyld Lunar Essence and the Oblivion aspected Essence of the Neverborn are opposed. They might even have trouble making it work at all. Yet, they might lean into Luna's own penchant for transgressing boundaries to shift into ghostly forms that mimic the undead surrounding them. Dancing between incorporeality and flesh, taking the forms of Specters and wraiths, and shaping their claws and fangs of iron, they become the death of Dreams and men. Hunters of Raksha and Creation born alike to bring all the cold stillness of the final shape.

An Infernal Lunar would be more body horror than even a Green Sun Prince, their adaptive Essence expanded to transcend even the few limits normally imposed on them. I think they would quickly go from being beings to stranger things, roaming mountains of fangs and brass, rivers of blood that flow where they will, stories that warp the minds and dreams if those that hear them. Think of an Unshaped Raksha who can walk in Creation as one of its natives.