About model and data exchange with 3rd party solutions: Revit, Solibri, dRofus, Bluebeam, structural analysis solutions, and IFC, BCF and DXF/DWG-based exchange, etc.
Tell your consultant to turn off the "pictureframe" or "drawingframe" varible in AutoCAD. I'm sure one of them knows about it. My experience has been, if they cared, they could do it. I always have to mark it up, even though I send a hard copy of our drawings...