MA3D will not
patch any fixtures of a Fixture Type, only 'models' of fixture types were brought into MA3D in the way you describe[icon in front of 'object' tells it 'type'--STAR=Model]....so,no, I don't believe there is a way to "Patch" your existing models as Fixture Types and have the positional data parse over...might be able to patch in real 'fixtures' then Duplicate using the other objects[models] as references...way too messy if it will even work, good luck!
Patch fixtures/devices in MA2 onPC/Console
first,
then utilize MA3D[visualizer] to arrange/align and add Scenic Elements per your unique show requirements/specs....that's all it does; visualizes the MA2 'Stage View' as a 3D 'shaded' environment complete with Material rendering instead of 'wireframe' as in the console's Stage View.
Rex