Wavey Capes changes how the capes work and makes them a little better, is it possible for the armors that have a cape (Divine, wither skeleton and Steampunk) to replace the cape (one that comes with minecarft) and work like they do with Wavey Capes?
I don't know if its possible to replace the minecraft one when the chestplate is equipped but for that I can just not show the one minecraft adds.

Forge : 40.2.0
Immersive Armors : 1.5.3

Once I have time to integrate my custom renderer (which supports epic fights and co hopefully), I also want to add animated capes myself, indirectly adding support for wavey capes.

indirectly adding support for wavey capes.

The dev of Weavy Capes , when I asked if the compatibility should be made from them or you, said "If the mod doesn't use the vanilla cape logic, then a compatibility layer needs to be made" so I don't know if this clears anything up.