This was your other suggestion.
It’s still 2 meshes one open. One closed.
Regardless of how you want to spin it.
It’s the same thing as to have 2 meshes - One for the lid and one for the object.
You still cannot bake lights with both meshes in the scene and you are therefore limited to dynamic lighting.
– using a skeletal mesh doesn’t really provide any gain even though it can include the lid and is therefore 1 less drawcall at a base level.
It adds overhead because of it being a skeletal mesh.
And it requires specific light options to light it correctly.