Converting Point Cloud into a Predefined Model in Place?

Short answer - you can’t.

Long answer. The best way to do this is by approximating the geometry to a mesh using dedicated custom packages/tools.

The only package I know in dynamo for point clouds is sastrugi and as far as I know it can’t do this sort of thing, at least not automatically.

Rhino and grasshopper have some tools that can do this to some degree using voxelization and mesh approximation/shrink wrapping but it is complex. Rhino inside can then bring these meshes (sometimes) into revit as a direct mesh.

Look into sastrugi and volvox for grasshopper as a starting point.